.@RobertKennedyJr reminds me that in America we have isolated a single religion as being capable of extreme acts: Islam.
This is wrong.
Every religion has its radicals.
There is Radical Catholicism, Radical Judaism, Radical Christianity, and more.
Discussion
I think it is only a matter of the religions evolution status. Christianity was a murderer religion centuries ago and it eventually became a peaceful one, but Islam is around 600 years late to the party and ( hopefully ) it will also finally reach to an equilibrium.
Btw, all religions do more harm than anything else imho