OK. On multiple threads you've been active on, including this one, I've spoken about Spire--a game all about bigotry and slavery (and fighting against the bigoted slavers)--and how I think it's well done. I've even mentioned writing slavery into a non-D&D setting I co-wrote with a friend.
What shouldn't be in new games is turning something as serious as bigotry and slavery into a just another encounter in the monster books or making all members of a species be evil, just because there are GMs who don't want to bother to come up with other motivations for the bad guys to make them deserve to be killed, or because "it's realistic" while not bothering to think about how the presence of fantastic elements would make a fantasy world end up very differently.
Things like that can stay in the old books--which are not going to disappear as long as there are pdfs of those books available. And even if WotC et al stopped selling those books today, there's still going to be plenty of copies floating around out there.