While I can't comment on men being so cumbrained that they get all hot and bothered over the faintest reminder that women have bodies, I can say that hitting "generate" on a generative AI frontend is like a pull on a slot machine or in a gacha, complete with the delay to build anticipation over whether what comes out of the inscrutable machine is good or trash. It's absurdly addictive, and synthesizing "push button, feel excitement" with only makes it more effective (same reason gacha games do waifu shit).

Not that that makes all the "so I asked the infernal machine to show me what it would look like if my idol Norman Rockwell painted a mid century pulp waifu just for me, as a treat," shit any less cringe and funny, of course.

they often aren't even generating much beyond the most vanilla shit.

I can say with 100% certainty that that's just a selection bias because people are more likely to post tamer things and more places will host and propagate those. R34 and fetish stuff is what's driving most of the community development of hobbyist models, and the things coming out of that general effort (mostly further finetunes of the heavily-retrained SDXL branch called "Pony Diffusion XL") are also better general purpose models than the strictly general purpose SDXL finetunes.