How about as a first step we recognize that language has power and stop using terminology that naturally stokes division, eh?

You're choosing a battle that is almost impossible to win (attacking people's identity) and which doesn't need to be fought (because most everyone agrees that racial supremacy is filled with hatred, cruelty, and wrong ideas). Why do this?

The ideas of racial supremacy have already been almost entirely divorced from the ideas of racial identity. Why link them linguistically again by insisting on making "White" and "Whiteness" do double duty as both a grab-bag of all the worst aspects of imperialism and racial supremacist ideas, and also as a label for one racial identity (as we now construe it)? Countless scholars, journalists, authors, etc. aside, how does this help?

This is especially important since almost all of the ideas of racial supremacy have been repudiated and are widely reviled, even if we're not free yet of all the associated assumptions which are themselves still causing significant problems. Because the ideas have been repudiated, if you find lingering effects and document them solidly, many people will naturally side with finding ways to reduce or eliminate the effects, if possible. But if you start conflating racial identity and racial supremacy linguistically, when racial identity is not widely repudiated and reviled, how are you by strengthening the association linguistically not just strengthening support for ideas of racial supremacy as people feel their identity attacked and leap to protect it and thereby also protect supremacy?

Seems totally counterproductive. You even admit it yourself: "When I say we need to get rid of Whiteness, people somehow hear me..." Yeah. Um. How about you stop saying it then! If you are being repeatedly misunderstood, maybe express yourself differently?