I do not feel ridicule is acceptable in any debate or discussion.
If we are going to win over any theists to the side of reason it certainly will be without ridicule.
I look at it like this: Theists ARE victims. This is just a fact, though they are not victims in the sense that they claim in these debates. They are victims in the sense that because of where they were born and who raised them (factors outside their control) they were taught dogma and gullability. They suffer from a well ingrained delusion passed down by parents or priests.
In the same sense I would never ridicule a victim of robbery, rape, assault or any other crime for suffering in the way they have I will not ridicule a victim of faith. (Though I've had moments where my patience was worn thin).
Now. I will not say the same of the teachers and leaders of religion. these such men and women deserve ridicule, they deserve to be tried and imprisoned for all their crimes, including the suffering of theists.