I disagree; there are "professional skeptics" such as those at The Skeptical Inquirer and Skeptic magazine who have devoted their lives to debunking the existence of such things as UFOs, Bigfoot, ESP, etc. They certainly don't believe in such things, and yet they are quite interested in them (or more precisely, belief in them). In the same manner, a "true atheist", while not believing in God, could be interested in others belief in God.
“In the same manner, a “true atheist”, while not believing in God, could be interested in others belief in God.”
Yes and no. At least on the surface, he is not interested in their beliefs. He may be interested in countering their beliefs. To be interested in someones beliefs implies more than dispassion; it implies more than just understanding. Interest gives itself over to belief, however subtle. The atheist is fighting himself on some level, wanting some part of him to win out. It is more psychological than logical.