Why are believers so hostile toward atheists? Is there anything atheists can say about our atheism -- or even just about our lives -- that won't make people look at us with revulsion?

The short answer is no, not really, because the self-styled atheist is usually an intrinsically repellent individual for the very reasons that caused him to primarily identify himself on the peculiar basis of one very specific non-belief. The reason that believers, agnostics, and even other atheists all dislike atheists who identify themselves as atheists is because they don't like annoying, dishonest, and literally self-righteous people with social handicaps who reject every objective moral or ethical code. You don't have to be an asshole to call yourself an atheist, but it quite clearly helps. After all, as the 2008 ARIS study showed, the even vast majority of atheists are not willing to call themselves atheists!