There have been cases of extremism and violence in every major religion, even Buddhism, but there's one religion that really raises the bar when it comes to murdering for their faith. The world, and everyone who follows that religion, would be better without it.

I haven't read the Quran, but I don't believe it mentions killing everyone who opposes or even threatens you or your faith.
That still doesn't say to me that religion isn't responsible.

There have never been vanilla "murder groups" or anything like that (except in military cases, and even then the conflict is usually created by religion). I can't think of any organized groups of people who come together to kill hundreds of others without any extreme belief motivating it.
It's always a "terrorist group", "religious group", etc. Even in cults and smaller incidents like in the Charles Manson case, that involved religious or spiritual beliefs. Religion, and extreme belief in general, is poisonous because it can convince people that they were created by someone to do something, when they weren't.

Not every mass murder is religiously motivated, but these uncivilized and uneducated third worlds are so much more susceptible to being manipulated into doing **** in the name of their religion. I feel like there is never going to be an end to "the war against terrorism" until religions that are prominent in the third world are completely extinct. Then hopefully all religion can go away, at least by my preference.