In fairness to your point, the 1E books don't really get into this stuff I think. I just reviewed the Elf and Half elf entry in the PHBs, and those mostly just stick with core mechanics (from which you could extrapolate culture I suppose but still it is mostly just saying things like what weapons they get bonuses on and what classes they can be). Same with the half elves. Even if you go to the monster manual (which the entries direct you to do), it doesn't really mention any of the stuff we are talking about (do keep in mind it is like 5 AM so take this with a grain of salt if I missed any lines in the 1E text). In fact all it really says is "They mingle freely with either race".
I would imagine though that a lot of people though were drawing on how elves were depicted in a lot of fantasy (not just Tolkien but stuff like Poul Anderson as well.
By 2E I feel like most groups I played with ran elves as fairly arrogant and disdainful of other races. In the 2E description it doesn't quite say that:
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It does mention they distance themselves from humans and that they dislike dwarves. Also in the 2E description at least the reaction half elves face ranges from fascination to bigotry. So I don't think the situation was meant to be that the majority of elves were bigoted against them, just that they might have applied that same distance and caution they had for humans
I like the 2E lore, but I think the main thing is it is more interesting to keep half elves as a racial option at the start of the game. Honestly one of the things I think weighs down many of the later editions when you compare them with stuff like b/x and AD&D is there is so much lore in sections of the book that really are about making a character. The lore can be more relegated to things like setting books and the game works fine. When I read 5E for example, one of the reasons that I lose interest (and I have nothing against it as an edition) is the lore in the character section. It just doesn't really appeal to me (and there is nothing particularly wrong with it, I just don't get excited by it). If it were presented more like the 1E classes and races, I could find whatever flavor I want in them (and it would be a faster read I think). So I do think there is something to be said for a more neutral approach. There is something to be said for the brevity in that edition (at least when it comes to stuff like character creation options). Don't get me wrong the entries aren't just one paragraph or something, but I think they take up like maybe a page column of text or a quarter of a column mostly and they almost exclusively focus on class abilities and limits.