You are right, I am not a Christian. But I do know more about Christian history than most Christians. Also, most self-proclaimed Christians aren't. Or at least most don't follow Christian principles in their lives.
It's true that I am not qualified to argue Christian theology, but being a Christian is not a prerequisite for that, either.
I do, though, have some common sense (I know, I know -- many here disagree) and I know a wack job when I hear one. And this guy is definitely in that club.