Is that really true, though? I can't think of any significant examples of games from the '80s or '90s that involved "in-groups punching... on out-groups", unless the out-groups in question were space aliens, nazis, fantasy monsters, hostile AIs, or the like.
Monkey Island is an absolute classic, of course, but this particular point feels almost like a retcon of present-day cultural assumptions into a specific context in the past where the objects of this criticism weren't really quite so present.
This is true, but those games were noted at the time for being crude and offensive. There was actually quite a bit of dislike for all of the above, and they were seen at the time as the exception rather that the norm.
I can think of the occasional bad-taste joke in an adventure game, but I don't think it was ever as pervasive as is implied.
Monkey Island is an absolute classic, of course, but this particular point feels almost like a retcon of present-day cultural assumptions into a specific context in the past where the objects of this criticism weren't really quite so present.