It would be hard for me to conceive of a less effective rebuttal; you’re completely missing the point.
It’s possible—admirable even—to design a fantasy world in which things “making sense” (according to your particular definition of what makes sense) is a top design priority. There is absolutely nothing wrong with that. It can get a bit unwieldy to do so, you’ll probably overlook a few things, and even if you nail it, somebody will inevitably complain that something doesn’t “make sense” regardless. Still, it’s a worthwhile exercise if you want to undertake it.
However, that’s clearly not a top priority for FR and D&D. It’s laughably easy to pick apart any number of design decisions on the basis that the in-fiction justification is insufficent, incoherent, or even wholly absent. It’s an exercise in futility, because it’s mostly completely beside the point. You could criticize ANY of the races for reasons very similar to what you’ve articulated.
We get it. You find halflings dissppointing. I hate gnomes, ironically because I don’t find them that interesting and I don’t think they’re distinct enough from halflings, elves or dwarves to have “earned” their place. What I won’t do, however, is put my own opinion up on a pedestal and try to argue that it’s the “correct” one. That would be absurd.