DEI wasn't demonized because it tried to fight bigotry. It demonized itself because it routinely became a dishonest two-faced movement that public denied to be discriminatory, but then privately implemented policies that explicitly discriminated on the basis of sex and gender.

When your leaders publicly condemn the idea that your company is discriminating on the basis of sex, but then privately institutes a system of reserving headcount for women, that'll make most people real cynical about DEI.