Mecheon
Sacabambaspis
I'd argue the problem we run into is D&D hasn't ever done anything to indicate why to keep just half orcs over going full orcs as they don't really do anything with the idea of it. Which falls into that "D&D hasn't really put their own mark on orcs so people just mentally put other orc ideas atop them" general statementFor the same reason that everything isn't a clone of everything else. When it's all the same it gets boring. Let LotR, Warhammer, Warcraft, etc. have the people orcs, and let D&D have half-orcs.
D&D's at least approached the idea of doing some stuff with half elves in Dragonlance and Eberron. Not necessarily always landing well, but they've tried to make them stand out from the competition and justify them being an option. Not so much with half orcs. Just "they're big and ugly" as the options and, well, enough occaisonally questionable stuff that the vast majority of this thread has been focused purely on the half elf side because there wasn't that much of a fanbase for half orcs. Like, I can't say for sure, but I vaguely recall there was more furror over losing gnomes back in 4E than half orcs
and, well, people orcs been a D&D thing long enough they can't backtrack away from it. Folks still complaining about gnolls not being playable and that was the cleanest attempt they did it on, orcs don't have anything that seperates that 'these can't be playable' gap