Have you thought about this enough?

There is something to the wisdom of crowds, but not only can people make mistakes, people can systematically make mistakes. Being black doesn't make you aware of how actions are globally applied. Being black doesn't grant you superlative knowledge of medicine and technology and intrinsic limitations thereof. Being black doesn't make you a mindreader. Being black doesn't make you immune to in-group favoritism. Being black doesn't make you independent, unswayed by any leader or social movement (necessary for crowds to display wisdom). It's very important to acknowledge that people who have substantial experience--racial bias directed against them, in this case--are experts in a way that people without that experience are not, and to note that that this is a great place to use the wisdom of crowds to good effect (i.e. to average over anecdotal accounts to find systematic patterns).

But it does not follow that because we stop ignoring personal experience therefore we've suddenly generated an infallible mechanism for determining something. And if you decide to just up and redefine the word that way, you now lose all the arguments (and some of the connotations) made with the old definition because they may not apply any more. You have to go back and check with the new logic. In particular, you have to be very careful to not lose all the moral force accumulated under a definition of "racism" that requires it to be prejudicial.

So this seems like a very dubious proposition.

Note also that there is no reason why anything like this is required for addressing police brutality. Way more than enough people were ready to do something about it after George Floyd. You didn't need to appeal to any racial group to figure that one out. But the momentum was squandered on Defund the Police (which claimed to not be naming its legislative demand, which is a really weird way to try to get things done) and various ancillary distractions (riots, etc.).