“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.
Hm...
I disagree. Example: there are people have devoted a fair amount of time to debunking astrology. There's no reason to think that their interest in some people's belief in astrology makes them believe in it in the slightest way.
Why should belief in God(s) be any different?