I feel like there's a more nuanced position, here.
I, personally, am a bit of a fan of playing "weird race" characters. It scratches my instinct to resolve dichotomies and my cultural anthro background really nicely.
But what qualifies as a "weird race" depends on the setting. So the more the assumption is Cantinaesque, the farther afield I need to go to play a weird race. Forex, in Sufficiently Advanced, the setting is transhumanist, so there are clones and net-denizens and constructed bodies and bio-engineered folks and all sorts of other sci-fi wackiness, as assumed character types. So first character I played was Amish. Fully supported character archetype, but against the grain of the setting enough to qualify as a "weird race." Playing a normal human with normal human capabilities was weird.
So, in that respect, I enjoy a human-centric campaign: it means that if I play gasp, a half-orc, I am aberrant and strange, which scratches my weird race itch.
In a Cantina-like setting, I need to get a bit creative (I remember the first old d6 Star Wars game I played, I chose to be a protocol droid. I was essentially forbidden from dealing damage to anything.). This isn't inherently a problem, it's just a change of tactics. Even the most inclusive setting has weird stuff -- sects that are normally villains, or "everyday aliens," or just something that rubs most people the wrong way.
It's also a matter of mechanics. In a game like D&D, where races are mechanically distinct, having a human-centric setting that eliminates options isn't very appealing. But having a game where, say, Dragonborn are re-fluffed as warrior humans from an old kingdom devoted to Bahamut (who just happen to have a breath weapon as a legacy), you can keep the human-centric aspect of it, without limiting mechanical choice to "only be a human." This is liquid easy in 4e, since no race has a real physical change. For all their claws and teeth, dragonborn don't have a bite attack.
Finally, it's a question of variety. Some times, I want the Cantina. Sometimes, I want LotR. Sometimes, I want a game where elves are totally alien, and dwarves are only legendary. Some times, I want a game where everyone is a monster.
I don't want to limit myself to only one option of setting.
For default D&D, I think something "LotR-esque" is warranted. Halflings, elves, dwarves, maybe a handful of other basically human characters with some weird quirks, nothing really with claws and fangs, nothing nonmammalian, nothing from another plane, preserves a sense of mystery while still allowing for some fundamental archetypes. It shouldn't be limited to that, of course -- Dark Sun brings you bug-people and giants, forex. But it makes a good launching-off-point, giving a basic humanesque baseline that can easily be added to, but probably wouldn't be largely taken away from (it's easy to see all of those in a more Cantinaesque setting, and you could see those being "weird races" or human cultures in a more human-centric setting).