I disagree, there are definitely extreme forms of DEI, namely when we’re talking about forced equal representation. Pools of potential employees are rarely perfect representations of society, for many different reasons. So if a company forcefully tries to have a perfect representation of society, that means they will discriminate against certain groups and hire less capable workers on average.
Let me explain it with a theoretical example: you are a company and the field you’re hiring in consists of 90 women and 10 men. You need 10 people for the job and want the most capable. Statistically that would mean hiring 9 women and 1 man on average, giving you the 10% most capable employees. But since you want equality you want it 50/50, so you hire 5 women and 5 men. That means that for the women you hired the 5,6% most capable employees, but for the men you hire the 50% most capable employees. So you get less capable employees this way, assuming both groups are equally likely to be capable.