If you rephrase "ending DEI" to "reducing the risk of getting sued when laying off x% of staff", does it make any more sense?

Nobody knows how to actually hire competent staff because it's a constantly changing bar: if you give people leetcode, they start cramming leetcode; if you review their GitHub profile, they start spending disproportionate amounts of time on projects; if you give them take-homes, they spend 5x the recommended time; if you give them real-world problems in a timed interview, that's probably harder to game, but some candidates will send a completely different person along. On top of that, some people just interview really well but aren't good 9 to 5. At a big enough company, you've always got a list of people who you incorrectly hired and want to get rid of.

DEI is a minor barrier to doing that for some cohorts. It's not that you hired incompetent people in XYZ groups to bump up your diversity numbers, it's that you hired incompetent people in every group and now you're unable to get rid of some of the ones in XYZ.

Also, let's not forget that some people are just genuinely sexist and/or racist and/or whateverist, either consciously or unconsciously. What happens when those people aren't held back by HR as strongly?