It isn't that sexism and racism do not exist. It's that you could have run the WHITE IRISH GUY and your vote total would STILL have COLLAPSED on that platform
So the answer to "why" cannot be boiled down to sexism and racism b/c EVERY AVAILABLE PIECE OF DATA says it was NOT the deciding factor. If you were right Biden outperforms Harris cause he's a white dude, and Trump gets more votes because ppl want to vote AGAINST the Black woman. That DIDN'T HAPPEN. Trump got 74 and 75M in 2020 and 2024