Again bad analogy with Brazilians. They weren’t brought over as slaves and stayed. They may have some sort of African ancestry, but not in the same way we do.
To your overarching point, yes, racial identity is defined by those in power if you’re talking about its use in institutions.
So why are we gatekeeping blackness and not talking about getting that power? Power doesn’t come through doing things the way those in power do. That’s just mimicry and there’s no power in mimicry.
And why would we want to do it like them?
Afro-Brazilians were brought over as slaves by the Portuguese and stayed. White Brazilians bred them out by intentionally race mixing.
Even in early America, there were "free people of color" communities that were mixed people and lived as mixed people, not Black.
See, Blackness isn't a thing to keep alive. Blackness is a position in society of a thing that doesn't have any rights or self-determination or protection. It isn't something to preserve.
Black folks hold on to Blackness by convincing themselves Adonis is Black despite having blue eyes and blond hair. That's a sickness.
I want to get rid of Blackness. You can't get rid of it if you can't determine who is a descendant of a slave and Black according to law and policy, so you can target interventions for actual Black people.
You will have a situation like Brazil, that has strong racial quotas and protections for their Afro-descandent population but you got White people running around saying they are mixed with Black and it's a great great grand mother.
They let people self-identity willy nilly, not rooted in the legacy of slavery and apartheid but feelings of their identity.
Why do you think indigenous people around the world don't let that shit happen? They are getting money and law on the books for their people. They are protecting a legacy. They ain't giving their legacy to people who never contributed. You can't walk around claiming to be part of them and ask for rights and protections by governments around the world.
Black folks don't want to self-determine because y'all don't wanna otracize a couple hundred thousand mixed people or a few million immigrants because you have standards of who gets to inherit your legacy. When they play language and identity games all the time to take advantage of policies that were won by Black people that come from American slavery.
So, yeah, power requires determining who is part of your group and who ain't. Going off of feelings and all that shit isn't how you get what is owed.
I am not for gatekeeping Blackness. I am for eliminating it. I want people to be people. I don't want people to live with the stigma of being a bottom caste. And in order to do that, you need reparations and an intervention. It can't be based on race but on heritage and lineage.