It's clearly a case for a house rule. I suggest you look into the bladesinging rules from the Complete Book of Elves, and let elves start with elven weapons with which they have +1 to hit.
Why would the Elves not use a useful tool, simply on the grounds that some douchebags over there also recognize that it's a useful tool?
By douchebags you mean my races mortal enemy for thousands of years?
In the US there were many people after World War II that would not use German or Japanese products, just because of the hatred still felt for those countries.
And that is a "short" war against two countries. Imagine that your people had been at odds for thousands of years.
I can completely see not wanting to use a weapon with a stigma associated to it, regardless of utility.
Again
What sort of silly army arms its soldiers with rapiers?
.
The kind that also armors them in leather and chainmail bikinis with a black spider motif, and uses hand crossbows as backup weapons.
I'm looking at you, Lolth.
It's worth mentioning that mountain dwarves have a similar kind of anti-synergy: anyone who can benefit from medium armor proficiency probably has little use for +2 to Str, and vice-versa. This isn't necessarily a problem in and of itself (dwarfishness has something for wizards, and something completely different for fighters) but it's something to consider when designing your own races, if you do that kind of thing.
That's why they gave them a +2 Strength rather than the customary +1 from a subclass. Otherwise they would be a horrible option for warrior types compared to hill dwarves. With the +2 Strength a fighter can feel confident that they are a choosing an effective warrior with either dwarf subclass.
Yes, petty humans did do that. But you would think that the average Elf would be smarter than that.