Modern BBSes aren't an issue -- they're out there, and they're pretty good these days -- but the lack of VC funding that lets them fund massive user growth isn't there, so the level of friction re: setting up your own remains high.
Discord's advantage is that it's not just easy to set up, but also free. You're not going to get that in the forum space anymore. ProBoards isn't going to invest the money into making them sexy anytime soon.
But can't the same thing be said about melanin levels? "There is no data suggesting there is a problem" is a door bad actors hide behind all of the time.