It became more important to hate white people and what they stood for than participate in Enlightenment culture, so they happily regressed to the cultural norms of, say, the Middle East or South America.

Multiculturalism and post-truth thinking was always insane nonsense, and the leftists have been drinking that koolaid for two decades, at least.

To hold up cultures that cut off clitorises in the bush and burn witches, or cultures which stone people and attack women with acid, or cultures which participate in unusual amounts of violence as co-equal to the culture which put us on the moon has consequences — but is a core part of a deeply racist leftist platform, that identifies racial groups with an essentialist culture, eg “black culture”, and views the co-existence of those “racially essential cultures” as the only means of racial co-existence.

As part of that, they formed alliances with questionable groups, such as the “black caucus”, which has long had links to black supremicists and have advocated for racist policies, and similarly sexist feminist groups, eg ones which advocate for female privilege in education even though men have trailed in college degrees since the 1980s.

So, basically, in the 1980s Democrats decided to build a party of racism and sexism to capitalize on social change, and we’re seeing the consequences a generation later.

People warned that this would be the outcome, but people were “right” and knew better.