I think the cinematics, including the more graphic romance scenes, prevents the inclusion of more nonhuman races because people will then start screaming furry.
People already scream furry, even though beastfolk and monstrous non-human races are in no way a new thing for DnD, and have never exclusively been played by people in the fur community.
Back in DOS2 days there were people against being able to take romance options as a lizard, for the same reason, people screaming furry, or even more stupidly, bestiality. I didn't see nearly as many people protesting being able to literally bone a skeleton.
