I think the devil is in the details. Most people support DEI as a concept; very few people believe diversity, as a concept, is bad. I'm personally supportive of DEI in general, but I have mixed feelings about it in practice.

My employer has a pretty broad and active program. They hold informational sessions hosted by the different DEI groups throughout the year. Those sessions provide visibility for the groups, but the content is pretty shallow. I assume it feels good to have those sessions for you if you belong to one of the groups though.

The actual things the DEI program effects are a mixed bag of results. Women and some racial minority groups have increased representation in the company since the groups were created. That's good. But if you're a white cishet male, you'll never encounter any of our recruiters. Recruiting works with the DEI groups to target their special-interest recruiting events. There aren't any inclusion groups that allow white cishet males, so we end up not going to any events they're allowed to attend. Of course, anyone can apply through public channels, but direct recruitment gets priority over web applicants. This effectively means we will only consider a white cishet male if there's nobody else. This structure would be wildly illegal if it were any other group that was excluded in that way, but instead we see that situation lauded as a good thing.

I don't have access to any career coaching or employee support groups because those things are all offered through DEI groups, and I'm not welcome to join any of the groups (I'm only allowed to attend virtual webinars as an ally). There are lots of outside of work team building events as well, but I'm not invited to those either.

I keep hearing that equity isn't a zero-sum game, but it sure feels like it is from where I'm sitting. I want to speak up and say I should have access to the same resources and benefits as everyone else instead of being excluded based on my race, gender, and orientation. But DEI programs have taught me that whites, males, and cishets take up too much air in the room and I should always yield to literally anyone else in the name of equity.

TL;DR DEI feels divisive when there is no inclusion group that includes you

It is that simple. In the other comment you made, I brought up Europe as an example on how to do things right. You are trying to argue semantics, when the thing is very simple. You don't call it prefferential treatment, you try to make it sound better to the reader, when it is exactly that. Prefferring candidates that are of a specific background, decided by people arbitrairly choosing the amount of leeway someone gets, or who those people are. It's downright immoral.

If I would complain, that my company failed when making a product because I went bankrupt, and then pointed a finger at a millionaire, saying "give me this contract instead of him because I come from a poorer upbringing", I would be laughed at everywhere. And this is exactly what this is.