D&D is a game which insists by default that species of sentient creatures can be inherently evil by nature, which no doubt links back to its central design as a combat simulator - if it's inherently evil, you can kill stuff with no moral qualms https://twitter.com/AnneofManyNames/status/1264568691217387521

In real life, if I am attacked by a wolf, I am morally excused from using violence to defend myself, because I can't talk it down

in D&D, magic lets us talk to anything, so the game (which has no detailed social mechanics) wants to morally excuse us from frequent violence

if you remove the "red dragons are evil" from D&D you are suddenly faced with the dreaded need to use the social mechanics (or lack thereof) and the game doesn't want that - the game is 70% tools to kill monsters with and 30% monster-finding tools

the game needs to force us to kill things to cover up the fact that there's no nuanced ruleset for dealing with things in another way, without a lot of freeform roleplaying (which personally I am happy to do, but that's nothing to do with the game)

for the record, this isn't necessarily a criticism, but it is an acknowledgement of the game's main limitation. D&D is a great combat simulator and a neat way to get new players into ttrpgs. But if you pick at the moral seams you'll only find straw and sawdust rofl