Atheists & Agnostics

I don't think it can be singled out to just be Islam. Christianity and Judaism have had their horrors as well. Often worse, I'd say. Pretty much any belief system that involves the supernatural (not that it would be a "belief" system otherwise) will eventually produce extremists. There is no limit to what can be motivated as faith-based belief naturally has an armor against moderation.

Edit: articles like these are what I would call Islamophobic, kinda. When you single out a particular religion over any others despite evidence that they all cause violence, you are attacking more the people than the belief system. That isn't to say the article is wrong, necessarily--just that it calls out one religion specifically, and helps to incite more hatred against an already hated population (though there are hunks of the article I disagree with). It ignores all the rest of the shit that other religions do as well. I have the same problem with Bill Maher's stuff at times: it's not that he's wrong, it's that he seems to take special delight in attacking Islam at times.