ad_hoc
(they/them)
I would say the situation suffers from a lack of a clearly defined standard of measurement. Back when I lived in Austin I had a lot of players from UT who said the exact thing you do; they swore that their depiction of another race was consequential, insightful, and thought-provoking.
I'm sure in their imagination they were making a brilliant performance, but to an outsider they were just overly dramatic wankers. We tolerated it because their stunning performance was just a few minutes of IC quips in the course of a session, and the game continued.
It's like PC backstories: people always think they have come up with something amazing, and you read them, smile, and nod encouragingly. It contains the same plot points as every other PC background, but you smile and wave them to the table because none of it will matter once the game begins and the usual RPG tropes take over.
I'm sorry that you've had consistently bad experiences playing the game.
Even though it has been happening since 1979, that doesn't mean it is like that for everyone. Note that even if you continue to condescend you're not going to convince people that they've been playing all wrong this entire time.
The fact of the matter is that you just don't know that many people from very many cultures. Humans are vastly different and they approach things differently and have different outlooks. I get that you have been playing the way you've been playing since 1979. And you probably think that you've played the game with many people - but, you haven't. There are many millions of D&D players from many cultures and sub-cultures and you simply have not played with them all.