There is nothing wrong with Religion. Religion is good - it gives people hope, a philosophical center, moral codes of conduct, etc., etc.
The problem is that People Are Fucking Nuts.
I mean, look at Catholicism today. Catholics, as a whole, are a very quiet and unassuming bunch. Oh, sure, historically they were a murderous, psychotic lot, being lead by power-mad buggers intent on political and material gain, but today they're pretty quiet.
So, since People Are Fucking Nuts, I guess we need to have lunatics, somewhere, where mindless sheeple follow power-mad leaders. Let's call them Evangelicals - you know, the people who deny climate change, and vote to legally discriminate against gay people, or to legally discriminate against the "wrong kind of Christians," and shit like that.
And since the Taliban seem to No Longer Be Nuts Enough, we have these ISIS bastards - really just another bunch of power-mad warlords channeling the mindless anger of the unhappy, ignorant masses against innocent targets like women, religious buildings, and pretty much anyone not the power-mad warlords.
Yeah. Not really much difference between those Muslim lunatics and the Christian lunatics, when really it all boils down to People Are Fucking Nuts, and lunatics will follow whatever "god" - by another name, right George Orwell? - is presented to them with enough authority and repetition.