The take that everyone thinks it's the fault of the group they least like is the most correct imho. The conservative dems all think it's because of woke and Trump's anti-trans ads. The xenophobic dems are blaming the misogynistic Latinos and Muslims, the voting-once-every-four-years-and-making-it-my-entire-personality dems are blaming the nonvoters, every single one of whom apparently had the time and energy to show up to the polls and faced no barriers whatsoever, and the handful left-leaning dems are pointing out that Harris ran a crappy campaign and campaigned with the scion of a war criminal more than her own VP (the response to which has been having standards is a privilege when Trump is on the ballot). The Marvel-brained dems are fun ones, they're running around saying that getting angry at the national party is like blaming the hero for not stopping the villain and asking why is no one blaming the Republicans for their votes (lots of overlap with the xenophobic Dems with anger directed toward crossover voters).

I really kinda wish I was doing a sociological study because the dynamic is interesting. Also sclerotic and nightmarishly involuted, but that's what makes it interesting.