The people most pushing for this don't actually care about racial or ethnic minorities, so much as they want to be the people that get to gatekeep and decide things based on their principles.
So at the very core, we have a movement of people with very specific principles. They argue that society MUST be collective and that classes matter more than individual rights. The rights of the individual are overruled by the rights of the class. How the classes relate depends on how the deciders and formulators arbitrarily rank them at any given time, but it's vague and deliberately so, so a multitude of people with self-interests cooperate to make them and their principles the system by which to determine this.
Class struggle theorists make no distinctions between the state and culture, and see the two as one and the same. Therefore, the state should dictate culture, and the people should follow it like good little robots. They reject notions of empirical truth and replace them with subjective, socially constructed truths by committee. What is right is a popularity contest and what adheres to the foundational principles the hardest. Everything else can shift any which way the wind blows.
These people have a very specific brand and way of doing things, and will make arguments assuming their point of view is already true and the operational logic of reality. If you reject their authority, you see their delusion for what it really is. A power grab. If you make the mistake of assuming they're legitimate, you find their logic leaves no room for even argument. Not because it's good, but because it's circularly self-agrandizing and affrming. Their beginning premise is, "I'm right."
And what they did was they framed their argument in a way that it appropriates the insecurities and tries to champion what they tell minorities are their "struggles," muddling the language of their rights and freedoms with their class-struggle ambitions. So they aren't allowed to champion their own struggles, they have to go to the class struggle theorists in order to be represented at all. It gives the anti-capitalists the clout that their movement is about civil rights or minority rights, and the means to get there is simply an afterthought with consequences they're not responsible for.
In reality, it's just a bunch of Marxists using minorities as shields and speartips to push social theories that conform to their principles and gatekeep aspects of our government, legal system and culture by asinine proclaimations they're POSITIVE are things, because how else could their system be true?
Find any kind of minority, they'll put it on a pedestal and make a big show about how more populous, adjacent minorities are actually oppressors of the little baby minority, and their group is looking out for their best interests. But it was never about helping minorities, it was about latching onto them so they couldn't even have a legal struggle without also representing Marxism, and Marxism gets to use legitimate civil rights struggles for illegitimate riders into the rooms where it's debated how best to remedy and service them.
They push this stupid expectation as a way to indirectly abolish culture from legitimacy as well as privilege certain groups while disadvantaging another (the majority.) Saying it's perfectly acceptable to negatively select against "the majority" (white people) but a crime and tragedy if it positively selects for whites.
They enable the narcissistic ethnocentrism in smaller groups without reprimanding it too much, in order to get them to be complicit with their power and give credibility to their authority, out of self-interest.
"Representation" by group in culture boils down to a disingenuous favors-for-favors argument, dressed up as something positive, and constructing it in such a way any that argue can be easily propagandized against as just hating minorities and justice.