Which villainous race(s) are next on the chopping block?

[Unoriginal]

I think that's perfectly acceptable for a book like a monster manual that sets a default and even says in it that the DM can change if they prefer. I'd argue that it would be a setting or race specific book that should offer other suggestions more in depth. I mean, in the end the purpose of the monster manual is to give the DM ready made opponents ripe to be fought, killed and robbed so DMs can get on with their dangerous adventures. So, I don't see anything wrong with saying "The default is this race was created to bed legitimate opposition to a heroic party. Or this race was created to challenge and evil party." and get on with it. The reason it was never a problem in the past is we didn't have people with access to lots of other eyes deciding ON THEIR OWN, that x race was a stand in for y real world human group and that's just horrible. In 40 years or so of playing I've never thought the monster races were anything other than monsters that took humanish form so the party could use their stuff and thus benefit from fighting them.

I have no issue with "X culture encourages Y, PCs want to stop/prevent Y, therefore most of the PCs' interactions with X culture is going to be antagonistic", but "those creatures are monsters therefore they exist to be slaughtered by the PCs" is an abhorrent concept for me.

You don't need to equate Fictional Species A with a real-life group to think that Fictional Species A are people who deserve to be treated as such.

It's just that part of being treated like people include "if you do things to others they don't like, expect they'll defend themselves".