There are secular people who commit mass murder and mass theft in the world, I have no idea why people care so much if people believe in a particular creation myth.
But you never hear anyone committing a crime in the name of secularism.
"I'm fighting so I can die a martyr and go to heaven to meet God. Our fight now is against the Americans." -Osama Bin Laden
When's the last time you've heard of anyone committing a crime in the name of atheism?
I'm not denying that the real reasons for war and genocide are the controlling of resources (the same reason most mammals fight), but fundamentalist religion offers an extremely convenient motive to follow through with belligerence. Some religious texts advocate war quite explicitly.
The problem isn't the belief in creation myth. That's ignorance, at worst. The problem is dogmatism/fundamentalism. I think most (refined) atheists take issue with these two more than anything else.
Maybe it is easier to hate other people's values than it is to confront genuine evil.
When other people's bigoted values stem from scripture, it becomes difficult to separate the two.
The problem is that religion claims absolute authority on the two most crucial questions that we face as humans: what is true and what is right. I can only speak for myself, but it's the absolutism that drives me nuts.
I also have to say that a lot of atheists care deeply about religion the same way that you would care about politics or someone else might care about NASCAR. We're just interested; it fascinates us. If it doesn't interest someone else, that's all good.
I can tell you personally that religion and religious belief interests the hell out of me simply because I don't get it and I happen to have an interest in the pursuit of truth and morality. When one institution claims a monopoly on both, and an absolute monopoly at that, it doesn't sit well.