All the younger players I know in person are inclusionists who detest or have no time for the gatekeeping of old - and all the halfling-haters I know in person are over the age of 40.
I'm a younger player, as I detailed in the OP, and I don't tolerate any gatekeeping, however, I completely disagree with the labeling of "people that dislike halflings" as "gatekeepers of the old". I've never said that anyone's fun was wrong, or that they shouldn't be able to play halflings, or that their fun is lesser than anyone else's, I just said that halflings aren't held to the same standards as plenty many of the other races in the game and want the game to change this in some way (to either make halflings have better lore or merge Halflings with Gnomes or even Humans by letting Humans be Medium or Small like Owlfolk and Rabbitfolk).
Also it's the younger settings from the 00s and 10s (like Eberron, the Nentir vale, and Exandria; all three seasons of Critical Role have had halfling PCs) that use halflings well and older settings from the 80s or even 70s (like Greyhawk, Dragonlance, and the Realms) that use them badly.
. . . But those settings almost definitely wouldn't include halflings in the first place if they weren't one of the "core" D&D races. Eberron makes interesting halflings (it doesn't make halflings be interesting, instead, it gives an interesting culture to halflings) and Exandria barely does any better than the Forgotten Realms in this manner (Lotusden Halflings are cool, but literally could just be Gnomes and there would be no difference). I know next-to-nothing about Nentir Vale, so I'm going to need an explanation of Halflings from that setting, if you would be so kind to provide it.
And another minor correction, there have only been two seasons of critical role, and only one of them included a Halfling PC,
and that PC was a Goblin for about half of the campaign, so I'm going to count that as .5 Halflings in one season of Critical Role.
There were two gnome PCs in Season One of Critical Role, so going off of the fact that only about half of season 2 included a Halfling PC to support this statement:
There are 4 times as many long-term Gnome PCs (2 of them)
than long-term Halfling PCs (.5 of them)
in the combined first two seasons of Critical Role.
But superficially the move to push halflings out would seem to be rejecting tradition. It seems to me to be more circling the wagons and making an attempt to throw out the group that was unpopular back in the day. While also trying to restrict races under the guise of making space.
I don't want to restrict races, I want to allow anyone to play any race that they want. However, if something as simple as letting Humans be both Medium and Small can practically invalidate a race, I don't think that they warrant having their own separate race. Obviously I'm not the one that's going to make the decisions here, but I think that halflings would function just as well thematically as their own race as they would being a sub-type (not subrace, sub-type, just like Small Owlfolk and Rabbitfolk are subtypes of those races) of humans.