I don't think this is true at all. I think it may play into to the hands of bigoted people but I see these as two very different things and see no causal link leading from white supremacy to CA in history.
Drawing the direct historical links, this person read this person, who read this person, who read this person, and so forth goes beyond the discussion and would probably be even more politically inflammatory than I already am. But I do there is a direct line of influence, a descent through modification between the 19th century writers and the modern movement along multiple lines right back to Condorcet, and from that you can see everything from White Man's Burden to Identity Politics and how different writers shaped that thought to where we are now.
To me it seems the intent is sincere. There may be bad actors but I am not going to project motives onto everyone who subscribes to cultural appropriation.
Nor did I. I don't at all question that the vast majority have the best of intentions and really believe that what they are saying is about restorative justice, any more than I claim that everyone who held racialist beliefs in the past was necessarily a hateful person. We can find many examples of people who very much assumed a racialist description of the world was a true one, that nonetheless admired, worked with, advocated for, and perhaps even genuinely loved people of different races. This juxtaposition of holding that a person's race defined them and yet not necessarily having hateful intent seems very jarring to us from our present vantage, but it really need not - we can find many parallel examples today if we take our blinders off.
I used to be a colleague of a black ex-boxer that had found religion. We were rather friendly and had long talks about religion and politics during breaks in the work. One day he told me, "It's a shame that you were born white." I laughed and asked him why, and he said, "I won't know you in Heaven, because white people don't have souls." He didn't mean it in any particularly hateful way. He certainly would have considered it incompatible with his religion to treat me poorly on account of my infirmity (if you will). He just matter of factly believed that white people through no fault of their own weren't really people.
The same sort of good intentioned racism permeates the "politically correct" movement. It likewise has parallels among the typical beliefs of my Southern forbearer 2 or 3 generations back. Many people who read the sequel to "To Kill a Mockingbird" were shocked at the portrayal of Atticus as holding racist views as being incongruous with the profound sense of justice he demonstrates in the first book. I found it very creditable, as far more reflective of reality than Atticus as ideal modern man. I'd met people much the same, that held to both the racialist view that race was a very real and inescapable destiny, but also that was no reason to mistreat anyone and that it was a sign of poor character - and beneath their dignity - to do so. "Politically correct" advocates tend strike me of being, at their best, of the same sort.
And at their worst, they remind me of the KKK members I argued with in high school, except that the KKK had the good grace to blush when confronted with their hatred and hypocrisy.
I do think Cultural Appropriation as it has come to be understood, leads to people being more divided and locked inside their own cultural paradigm though. But I don't believe that is the goal or that it arises from a belief in racial essentialism (or supremacy).
I believe that not only does it arise out of racial essentialism, but that the language of it is frequently taken up by those that believe in a racial supremacy or superiority.
And without getting into the details here which would be even more politically charged than this thread unavoidably is, the general theory that "political correctness" arises from a response to racial essentialism that argues against the outcome ("white supremacy") but not the axioms in which that theory is grounded, or which in in the case of feminism argues against the outcome but not the axioms of male chauvinism, is not I think a particularly surprising or strained one at first glance. Leaving aside the specific writers that armed the feelings with ideas and language, I generally proposing the following:
a) People that are abused, often are observed becoming the very thing that they hate. Thus, people respond to abuse with abuse, becoming abusive at a notably higher rate than those not so ill-treated. There is nothing particular hard to understand about how injustice damages ones trust in justice.
b) When you are steeped in a particular cultural paradigm, it's often very difficult to notice the framework for it. It's very natural when presented implicitly with A, and then the claim that A->B, to argue against the implication and not the factuality of the initial claim. It just becomes an unconsidered fact. For example, when someone claims, "Whites are superior to blacks.", and you are living in a world where the social reality of being black versus being white is so self-evident, it's very difficult to question the claim on the basis that maybe race is principally an artificial social construct and much of what you think of as defining who you are isn't really part of your skin color or any other physical part of you. And, even when you do accept that it is, it's very hard to avoid coming back to that idea of essential difference and reinventing it.
c) The same tempting beliefs that led people to propose white supremacy or male supremacy, are still present in people who are arguing against those beliefs.
