Remathilis
Legend
Because orcs and drow graduated from Monster Manual to PHB. Goblins and kobolds didn't. It's that simple. They are PC species first now.But why do goblins, kobolds, and so many other former humanoids still need monster statblocks if orcs, drow and duergar don't?
I've asked this question several times. No one seems to have an answer.
WotC isn't saying it, so I will: humanoids are for PCs now. Other types are for monsters. Yes, NPCs can humanoids and PCs can be other types, but the default assumptions is that. The goal is to remove the notion that PCs are supposed to slaughter other humanoids and to instill the notion that humanoids have defined alignments and cultures. Thus they moved as many former humanoids as possible into other monster categories so they could keep them as monsters.
You can disagree with that decision (I expect you will) but this is purely a way to make it easier to kill goblins without getting into odd assumptions about genocide and free will. Goblins you are likely to fight are fey beasties no different than boggles or redcaps. Gnolls are fiends, not people will families and moral quandaries. It's their way of trying to preserve the idea these creatures roles in the game are as monsters first and foremost.