To be honest, it's mostly "Christians" and atheists that do that. Atheists because they think Christians are morons, and "Christians" because the vast majority of them are self righteous hypocrites.
Now, the "Christians" I'm talking about are just regular people who go to Church on Sundays and call themselves Christian. "Christian" is merely a title for them. They aren't real Christians and they don't even know what a real Christian is, hence the quotation marks. (like the first two "Christian" commenters, for example).
I'm willing to bet that you've never even seen a real Christian in your life. Mostly because we're a rare breed and you can't find us in Churches. All the "Christians" in Church now days are exactly like everyone else in the world. There's nothing that separates them from the others because they've been corrupted and want to fit in and be accepted by everyone else. The REAL Christians are the ones who preach the stuff in the Bible that Churches won't even whisper of. They're the ones who get kicked out of Churches because they preach the truth. I should know; my family has been kicked out of several Churches for nothing more than saying what's in the Bible. I doubt you would understand though, because in the same way that only a mechanic knows what a dual overhead camshaft is, only a Christian can see the hugely important, yet seemingly minute differences, within their religion among themselves.