Even if doing so might advance that agenda in the short term, and I don't think that's the case to any great degree, all it takes is a shift in who the gatekeepers are for this to go very wrong.

Just look at how many countries outlaw all kinds of speech on the basis of this or that religious group being offended by it. Who gets to represent marginalised groups and say what they are offended by? How many or what proportion of them need to be offended for it to count? It's a quagmire.

That's not free speech.

And just to counter your actual point, what about a lousiana white person who's family's been living in poverty for 100 years? Do they get free speech? Or not, because they're white?

It's not unambiguously true that freedom-of-speech itself is substantially responsible for anyone's loss of other rights. We can't even have a public conversation about this without freedom-of-speech, where all relevant ideas and evidence can be openly evaluated, unless there is essentially no gatekeeper (committee, policy, "filter", etc.) deciding on what is relevant or permissible speech. We will only have biased answers if we bias the discussion.

Further, even mere perception about the bias in the discussion (caused by censorship etc.) causes some people to disengage from the discussion altogether, and facilitates the "silo-ing" of groups of people who have little contact with each other. That is not a recipe for a functioning pluralistic society, and ultimately for peace itself.

The only thing restrictions on free speech incentivise is conformity to the ruling party's policies and there is an implicit assumption here that the democratic parties values are really the correct ones - which many people of colour will dispute.

The moment the Republicans take over (which they will inevitably considering how few campaign promises Biden has so far delivered), they will turn this on groups like BLM and the Antifa movement in general.

Racists never needed the protections of free speech to argue for denying people their rights because those views already had widespread societal acceptance.

Now that explicit racism is no longer the norm, organisations like the Klan need to rely on free speech protections, but thats only evidence of how unacceptable their beliefs have become.

These earnest arguments that limiting speech will help protect people are terrifying.

Your freedoms should _never_ be contingent on the expression (or lack thereof) of a particular political ideology.