In fact, it never was. People like to have straightforward answers to things without having thorough investigations that require them to ponder over subjects longer than they feel like doing, especially if the subjects involve the question of various ideologies and have some degree of confrontation with various people. Religion is one such subject unfortunately and it doesn't help that it has been scapegoated convincingly by the very people who claim to follow the religions themselves.
I will use mainly the history of the Prophet Muhammad (saw) in this article as that is the most well known to me and the most example filled. They are also one of the most recent of the big religions so their progress or regress is much better documented. I will also include the history of the founding person of our community whom we believe to be the Promised Messiah, Prophet Ahmad (as). For more info on that, read my first blog about what I believe. I will also refer to the followers of the prophets as believers, the society, and the community.
Since the beginning of humanity, in the belief of the Muslims, religion has been a way by which God communicated with humanity. He would send prophets who would bring laws and some that would refresh and maintain the messages of previous prophets that brought laws and he did this to all peoples. In every case though, there was opposition as there would be to a new message of any kind which makes radical amendments to society. Eventually though in the life of the prophets or following them, these opponents would convert to that message and the people would be dominated by that faith. However, many of these opponents and even the supposedly sincere did not change because they saw a great truth and benefit in it for humanity but it fit their needs in society.
A lot of the opponents would usually be of the people who are the previous ruling class of the society the prophet came to and naturally would be the first to antagonize the prophet, his followers, and his message. When they converted though, not all but some would do so only because they realize this is where their society is headed and instead of dying out, they should adapt to the new society and take control within it. Some would even realize that before the opponents and from the beginning they would they would convert only to go along with the crowd and insert their authority into every affair whether it is needed or not.
Over time with the death of the prophet and his successors, believers would stray from belief not because they never believed but because they believe their prophets to be the root of their faith and if he is human and must eventually pass away, then his faith is as such and to them can be dictated any way they want afterward. Those who were always mischievous and joined the society because it was where society was going take these opportunities to lead the communities how they wish and interpret the messages of the prophets how they wish.
The other trouble that arises during the lives of the prophet and his successors is the education of believers both worldly and spiritually. As the message grows and spreads in the regions it is for, it is harder to educate the followers equally and as quick as the message is spreading. If many of these people cannot be taught their new faith properly and in detail and they bring in much of their own culture and beliefs whether or not they are accepted in their new religion. It is especially difficult if there already elements in the community who are trying to subvert the message being spread and they spread a corrupted message and there are such elements in the new peoples as well. They take great advantage of the lack of education in the faith of the people the most.
These various aspects contribute to the original reasons by which many religions had supposedly turned to violence and become "the cause of all the world's problems." It is of course apparent that it was not the religion but the people themselves who changed their goals in faith from peaceful to oppressive. In the latter days of all religions, it is blatantly apparent that religion had only become a means to carryout whatever the leaders required of their citizens. Going on from the above mention of people lacking education being led by mischievous people, they know that it is a touchy matter for the people and so they exploit it like anything can be exploited
Religion is not needed to create the disruption in society that exists in place where religious fanaticism is but its a good medium because people follow it on a wide scale and its a way of life. Anything that people can strongly affiliate to can be used to create violence. No better example of that exists I think than in the modern century where we have had wars with Fascist, Imperialist, and Communist countries because they had different political ideologies. I don't recall religion being used by them to expand their territories and wage world wars and regional wars against people who didn't do anything, 2 of them didn't even have a religion if I'm not mistaken and the other one dealt with superiority as a people, not superiority in belief.
Looking at the history of Islam, there were people in the time of Muhammad (saw) who were known to the most devout Muslims as the Hypocrites. Whenever the Muslims would be weakened by a loss in battle or some treaty or expedition they had to carry out or even some little societal disturbance, they would always be the first to make a big deal out of it to the rest of the Muslims and take advantage of the situation to create their own spheres of influence on them. Thanks to God though, every time they were subverted by words of the Prophet (saw) or his actions because as hypocritical as they may have been, this wasn't modern day extremism and they followed as much as they were required to still be called Muslims but not be involved in any great undertakings.
At the death of Muhammad (saw), many uneducated peoples who had joined Islam in the life of Muhammad (saw) left because of the lack of education and grief of his death. It helped that many of the same people in these peoples who joined to take advantage of the situation stirred these people to leave and rebel against the newly unified Arabia. These were subdued not because they left Islam but some did not pay their taxes which they thought unnecessary at the death of Muhammad (saw) and others because they joined the armies of the people who stirred rebellions and were threatening to tear apart the state. It has become imprinted in peoples minds that it was because of apostasy because many of the rebellion leaders claimed themselves prophets as well but again it is only another example of how religion was only abused and scapegoated both by those leaders and historians who misinterpret the Muslim action against these people.
Later on in the careers of Muhammad's (saw) Caliphs, two were assassinated because of the machinations of said people who were either part of the crowd because they thought it in their best interest or had been corrupted by said people. The first was the third successor who was doing a standup job leading the state and even had the Quran standardized as there were many different versions where the verses and chapters were in different orders and such. The antagonists reasoned to their followers that he was acting as a corrupt leader and was to be deposed violently on religious grounds yet they only sought disorder so that they could take control of the state. This is confirmed in the assassination of the fourth Caliph.
The last Caliph of Muhammad (saw) was trying to regain order in the Muslim state before he was to go after the miscreants but the family and closest followers of the former Caliph wanted quick judgment on them and on this, no reason of religion, was a war fought. On both sides were these people hiding when they came to clash in several unfortunate battles and both sides they gave their advice. When the Caliph tried to make peace based on religious reasons because Islam does call for peace wherever possible, they treated him just like the previous Caliph and killed him for the same flimsy reasons because it was them who did not follow the religion but only used it.
After the fourth Caliph, many leaders and dynasties succeeded him but none are considered legitimate Caliphs of Muhammad (saw) as they weren't chosen by the people or their advice and many were like kings instead of Caliphs who spent more time with spiritual matters. It was when the true Caliphs fell that the education of peoples far from Arabia started stunting and the Muslim world started going further and further away from Islam. The kings, as I'll refer to them because I don't believe them to be true Caliphs, utilized Islam more and more for the purpose of conquest and then subjugation of minorities and just all out violence the further time went on.
In my community, the Ahmadiyya Muslim Community, in our beginnings, there were numerous people that joined that would later leave and in the life of the Promised Messiah (as) were studious followers but showed signs of not truly believing or having faults with what they were following. It was with our first Caliph that they started machinations of trying to get rid of the system of Caliphate because they thought a group of people would be the better to run the community and the Caliph remain a figurehead. He had many followers though as he was the closest follower of the Promised Messiah which is why he was elected as he was.
It was in the time of the second Caliph was elected very young but was quite learned as he was personally taught religion by his father, the Promised Messiah (as), and the first Caliph, that they just got up in left. Many of them were middle aged and had spent a great deal of time in the company of the Promised Messiah so they refused to be led by him and chose to start their own community. They've written a number of books on why they split and have attempted to support religiously why they did and they have even gone so far as to reject the very basic reasons as to why they were a separate community in the first place despite the fact they clearly believed it while the Promised Messiah (as) was alive.
Mischievous people will always be around and we should be able to examine them and see who is doing something for an alternative reason aside from allegedly "following his religion." On that note too, religion is an ideology, not a person, you don't just follow it blindly, you interpret and follow it. If you interpret it with mischievous intent, you will get mischievous results and it will not be the fault of the religion as it is only a message.
Blogger's note: I realized after writing this that I had already written a post on religion being used as a scapegoat and I was tempted to delete this and do something else but then I realized some I addressed points in this which I did not cover in my previous post. Further more, I feel that this a response to the bigger issue which has plagued the view of all religions as a whole in the eyes of the people of today and it should stop because it makes people as narrow minded as the people they are criticizing for using religion for violence. I also included examples in this one from my own religious community and the time of Muhammad (saw) as I have read some more on their history.