Finding D&D, part 4! This one is scaring me. Remember how I warned that the one about fundamentalism and the OSR wouldn't be insulting? I fear this one can't say the same, and even if it doesn't go too far, I know it's going to gore a lot of oxen.
One point I develop in the video, but mercifully cut about 10 minutes at various points of ranting further, is that I typically don't mind interacting with fundamentalists, if we're talking about regular people rather than careerists. Unless they've gone fully reactionary whackadoo, in which case we're talking about real danger, they're typically capable of real conversation once they realize you're not trying to make them stop handling snakes, or making fun of them. (This applies to evolutionary biology and real life as much as it does to D&D and made-up elves.)
Essentialists are another story entirely - there's just no dealing with their two-ply teflon of knowing they've discerned the core/concept + being certain they've arrived at it through pure reason and thus any disagreement must be due to the other person's confusion ... at it's worst, it's impenetrable willful stupidity armed with smug, over-intellectualized certainty.
But then again, this is where the consistently best and most fun published game design that draws upon D&D fantasy comes from. When it comes to doing, they genuinely do.