Thanks for the considered reply.I mean being real, it doesn't in a hard sense, but does in a soft sense. I'll explain.
It's not like any measurable number of people reject games outright for having species-based stat mods or the like, but the issue is really down to how essentially harmless physical stuff like "halflings are small and strong for their size so very nimble" (hence +2 DEX -2 STR) can easily trend into a portraying orcs identically to how racist psychos from the 1950s portrayed Asian or Black people (mentally subnormal, inherently savage/barbarous, reproducing rapidly, incapable of building real culture, possibly physically stronger/tougher, due to their savage nature, etc. etc.). If you don't think that slide can happen, well 5E hard-proves it can, because it happened between the PHB in 2014, and Volo's in 2016, which like, that's incredibly rapid movement, and from well-meaning people who I genuinely don't think were trying to be racist, they just managed to because certain tropes clump together (especially in the minds of people raised in racist societies, which is to say pretty much all current societies).
The real problem, being very honest about this, isn't physical stat modifiers by themselves. It just isn't. They're caught up in the fact that mental stat modifiers often are basically involved in depictions that essentially (sometimes very precisely) replicate massively racist ideas. INT penalties particularly. And it's hard to get rid of just mental stat mods - I mean, it's not, but it would be too much of a leap for a lot of people I think, so it's easier to remove both at the same time.
The reason it caught on so quickly is that it also lines up with allow more diverse and interesting character design, because then you can have typical characters without them just being ones who push against the default modifiers (which isn't a mechanically or even really conceptually interesting thing to do, and itself potentially plays into racist tropes).
I don't think there's any real objection to games which have stat mods in existing, but I do think there's a reasonable case that it's probably not the right way to go for a mass-market-oriented game, and especially not if you're incredibly confident in your abilities to be sensitive, and rightly confident.
Because again, WotC absolutely screwed this up. WotC who have, relative to other RPG companies, infinite resources. A bunch of well-meaning people, some of them minorities themselves (though very few ethnically so at that point), managed to screw this up.
The other issue with stat mods is that they're not very interesting or evocative compared to more specific abilities.
Not directly related to what you're saying but one thing that I was thinking about whilst travelling was that Star Trek has sort of addressed this to varying degrees from the start, albeit particularly from TNG onwards. Spock isn't Vulcan. He's half-human, half-Vulcan. Vulcan logic is a cultural trait, not a biological one (c.f. Romulans), and without it, Vulcans aren't really smarter than humans (they are stronger, though). Worf is Klingon, but in Star Fleet, and in fact is rather atypical, showing his human upbringing has made him very different to a Klingon with a traditional upbringing, despite having fully Klingon biological traits.
You make a compelling case for making fantasy rpg settings humancentric with relativistic morality.