Well, when trying to run a human centric campaign. You have players playing anamorphic ostrich bards and dragon men and turtle people. I have to put limits down on what is appropriate for my game.
But players expect to be able to play turtle people and cat people and elephant people. So I have to cut down access to those races. But I probably assume that these races have special abilities or powers or skills that make them superior. So I guess the problem is with WoTC and with D&D 5E.
Players always want an edge... and playing a bird person or turtle person, or dragon person, or cat person, or elephant person gives them an edge over 'boring' human.
The game encourages a typical D&D party to be something from an escaped circus troupe because mathematically they make weirdo amphomorphic races superior to any other races.
Well, you might ask WHY is it you "have to put limits down." Are the players not equal participants in the game, and thus equally entitled to participate in defining the genre and milieu? I mean, sure, you can go and say to whomever you want to have play "this is a fantasy world that only has elves, dwarves, half-ors, and humans" if you want. Are people not wanting that? Then I think the problem is you just need to adapt.
Nor do I agree that other races are superior, mechanically. The Tabaxi I'm playing in a game now seems perfectly in line with the Mountain Dwarf I played in another game (actually the dwarf was probably quite a bit tougher). I'm no 5e rules guru, but my experience with players and the 5e rules tells me there's no strong selection based on 'optimization'.
And again, if the crowd you are playing with is such heavy optimizers that all they will do is play some theoretically ideal PC, then the problem is who you're playing with! Either cater to their desires, or find a different group.
Maybe your game focuses too much on mechanical stuff, and probably combat? I don't know, but that generally highlights optimization and encourages some of that charop mentality. Trying to horde all narrative control of the game has that effect also, as players then seek to stake out some other area where they can exert influence in the game. Try focusing more on PCs backstory, social ties, using inspiration, and less tactical play. It might help. But mostly, give them what they want! If your favorite setting doesn't mesh too well with that, either re-imagine it or go invent something else (and I would suggest doing so with the players as equal partners in the endeavor).