Have you ever convinced a religious person to become atheistic? How did you do this? How long did it take? Were the people in some sort of life crisis, or were they just living along?
This is probably a quite difficult task of persuasion. So stories how people were successful at it could be very interesting to improve ones' persuasion abilities.
Relatedly, it might be interesting to know what religious groups have gathered on techniques to convert people to their religion - are there some manuals/techniques floating around?
The antecedent of your conditional is not the case. I do not have a definition of 'sexism' and am fairly confident that such a thing does not exist. That is, I am skeptical that there is a list of necessary or sufficient conditions that will match the folk-term 'sexism.'
However, the particular joke I linked to is the sort of joke that is often labeled 'sexist' by the sorts of people who care about such matters. That is good enough for me. More importantly, the joke is based off of (what seem to me to be) unjustified premises.