You may not be familiar with US history, but it was an extremely segregated society back then with many lynchings occurring for any black people who stepped out of line. Black Americans frequently had to make parallel systems just for their communities since they were often not served by services run by white Americans.

So in this case the skin color of the people who created these newspapers is an important historical contextual point. Additionally, it’s simply a fact of the matter being discussed and as such it isn’t racist to mention a basic fact.