I think that, in general, a fairly substantial number of voters got tired of hearing about DEI being shoved down their throats all over the place and that got tied to politicians, deservedly so or not. Even a dummy like Trump was able to see that and he jumped on it running campaigns around racism for 12 years. There was a chance for a politician on the other side to counter that with some kind of intelligent nuanced view on DEI, but all they did was add to the problem by hammering Trump and his followers for his bigotry. That didn't help.