Honestly though, I have no idea where to find the information we need to settle this disagreement.

That's an important question, but one for which I have no answer.

I agree that we should act as though religious beliefs are crazy (in Eliezer's sense of the word). The question is, what does it mean to act that way?

What I mean is that our reaction to someone who says, "I believe that Jesus is the son of God" should be similar to our reaction to someone who says, "I believe aliens are trying to kidnap me".

Okay, just so long as we agree that "what it means to act as though a belief is crazy" isn't something that you ought to define however you like. (As though you were to argue "It's ridiculous. Therefore, by definition, I should ridicule it.") The proper way to act is not something you can determine just by analyzing what "crazy" means, or just by establishing that it's not okay to have crazy beliefs. The proper way to act is determined by what will in fact change the world into a state more like it ought to be.

If you're right about the history of the acceptance of homosexuality, then that is some evidence in favor of your position.