Why did the Progs eliminate all reference to black patriots in the Revolutionary War? Why do Dems keep it up?

There were quite a number of Black Contributors to the Revolutionary War and in other ways. All reference of important Patriots through out the years has been pretty much scrubbed. The Contributions of the few mentioned are pretty much scrubbed of patriotic efforts and many of their praise of the Constitution as an anti Slavery doent for all man kind. Scrubbed of their objections to different treatment determined by race. Scrubbed of their comments concerning moving on without bitterness and making a place in this country in which all residents were fortunate because of the freedom the Constitution provides to all. Scrubbed of references concerning the continuing struggle for individual freedoms for all in this country since before the Revolutionary War itself which included black men. Free Black men who were seen and treated as equals and were great contributors in so many ways to the USA. WHY?