You know, it's interesting that you posted this. I have the same experience. I often wondered why someone would take the position on the soap-box like Dawkins would. But I listened to Dawkins and Hitchens when asked why they do this. And they had some valid answers.
Someone has to remind the world their head is up their ass. Otherwise we won't change, not to mention give control over to these delusional people. The reason they hate Atheists the most is because Atheists have the strongest message that has the most solid backing.
Because of that, I now have a stronger voice and call people out on their religion a lot more often. Not the best results, but some people need a wake-up call.
Cheers