If you've ever worked on a large project team that's accumulated a bit of human detritus, it's easy to understand. DEI people aren't just useless deadweight that adds no value, they're productivity drains and sap the output of everyone else around them. These oxygen thieves don't just sit on their hands collecting pay checks, they're constantly bombarding the people who normally get shit done with useless demands or requests for changes that cause progress to grind to a halt.
Instead of letting competent employees build something and move forward, these time vampires want to have a meeting about every decision or form committees that have to approve everything. No meaningful work gets done and eventually someone higher up realizes that everything is massively behind schedule and over budget and human tonsil stones responsible for all of it are pointing fingers in every direction but back at themselves making it impossible for anyone on the outside looking in to untangle the mess and remove the useless people.
If the upper management doesn't scrap the whole thing right there, they'll try to throw good money after bad and bring in some outside help to fix it. Even if that outside help is competent, anyone who's read the Mythical Man Month already knows that this won't fix the problem, and almost certainly makes it worse. More likely though, it's another batch of useless consultants that exacerbate the problem. Eventually the entire thing will get canceled or the company will force the stillborn product out into the market, hoping they can ride on past successes and customer loyalty to recoup some of their losses.