Why Do Atheists Talk About God?

If atheists don't believe in any god, why do they spend so much time talking about it? This is something that comes up when engaging in such theist-atheist discussions. It's usually used as a cheap attempt to discredit an atheist's points, or prove that atheists don't really disbelieve in god. Of course, such attempts are ridiculous, and, well, stupid.

But it's not an unreasonable question. Why would you spend so much time talking about something that you don't think exists? I can't speak for anyone else, but here are my reasons.

1. It's interesting. Just because something doesn't exist doesn't mean it's not interesting to think about. I also like talking about elves and alternate histories. 
2. I want to know the truth. If a god does exist, I want to know about that, and I won't find out by sticking my fingers in my ears.
3. Finally, and most importantly, because people use their belief in god to support teaching creationism, banning abortion, bashing gays, mandatory public school prayers, and many other flagrant infringements on rights.