Sounds like an argument in favor of sanitizing so the possibility of getting it wrong is removed. Is that what you're advocating?
No?
Look, there's a big difference between saying "in some settings, <insert race/heritage/species> suffer from discrimination because of <insert stupid reasoning here>" and maybe include a a sidebar on how to handle this effectively, and actually writing an adventure or setting book that (a) has that discrimination as a True Fact and (b) handles it probably not that well.
As an example of the latter, take a look at the way D&D handled the whole duergar thing back in Tome of Foes. The duergar got mind-raped and enslaved for centuries, but the
typically lawful good dwarfs and their
typically lawful good gods decided that it was the duergars' fault. And now the duergar are
typically lawful evil and because of that deserving of any hatred the dwarfs and their gods show them. It's basically victim-blaming an entire culture of people for collectively failing their Wisdom saves against a much more powerful foe!
I know I don't want D&D to handle PC bigotry in that manner. I would
much rather them present the background, adjust their alignments because "racial hatred" and "lawful good" do not mix (since I'm not going to get my wish with D&D and have them remove racial alignments entirely), and have a section that says that many hill and mountain dwarfs hold certain prejudices against the duergar. And--and this is the most important thing--
have those prejudices not be true. See, the hill and mountain dwarfs are
justified in hating duergar because duergar are evil. The same is basically true for every time there's a race that suffers prejudice in D&D. There's always a legitimate reason for that prejudice, and that reason is never the fault of the bigots.
Yes, Tome of Foes was about 6 years ago now. Maybe they've improved since then; I don't know. Do
you think they have?