That turns out to not be a particularly effective defense for hurtful words. If someone is hurt by what you say, and this is your defense, that means that you find their pain funny, and you are willing to risk their pain for a laugh.
Not to mention that archetypically, that defense is applied after the fact, held up as a shield only after finding out the audience isn't having any of it.
All in all, what is needed isn't a "neutral" conversation - too many deeply held beliefs, things people us eot build their personal identity are involved. What's needed is a sensitive and respectful discussion.
But you want to make jokes. So, that's not in the offing, now is it?
Let's get this straight. The joke did no rely on anyone's pain, it was humorously comparing a book of fantastic stories into other similar books on this forum of fantasy enthusiasts and was a serious answer to another poster's question of why this particular Kickstarter was featured and receive attention: the subject matter is very widely known.
And yes, it contained an implication that I personally might not consider the book in question to be factual. And I claim that people censured for expressing such an opinion is a far greater harm, than the potential hurt experienced by some members of privileged hegemonic religion by hearing that not everyone shares their faith.
Another poster was infracted for bringing up various atrocities in the source material and asking how the adaptation would handle it. I think that is an important topic, and there was discussion about similar matter regarding one of the Greek inspired setting... Odyssey of the Dragonlords, I think. I think it is rather unreasonable that the source material being part of major religion would make it except of such examination and critique.
What you demand here is not politeness, it is deference. And one that absolutely is not afforded to marginalised religions here. I strongly feel that we should be able to freely talk about any mythology when it is used as source material of a game, without the fear of being infracted for blasphemy.