The problem with DEI-as-implemented is that it often not only contains overt discrimination against a group (based on a protected class), but also prohibits any criticism of this. When someone is being discriminated against, not subtly or silently but explicitly, intentionally and overtly, and then punished for daring to complain about it, that leads to a lot of resentment (both by the people directly affected and by other members of the same class that observe both the discrimination and the silencing).

I'd say that resentment is justified; unfortunately, I suspect the backlash will primarily hit the people that the DEI policies were supposed to help, rather than the perpetrators of the discrimination.