You're right, they aren't the same question–but that's what my brain brought up when queried with "what would you say if asked to debate the existence of God?" Somehow just saying that "no, I think that God doesn't exist for reasons X, Y, Z" doesn't seem to be enough. I think this may be because of the "arguments as soldiers" approach–if I tell someone I'm an atheist, but don't go on to clarify my beliefs on all those other questions, the assumption tends to be that I must think theists are stupid, stupid people.

I think it also might be a strategy I use to increase the feeling of "being on the same side" when talking to people who I know are theists, since not clarifying might lead them to believe that I'm, in some sense, their intellectual enemy.