Well what I believe is that a good number of your activist Democrats or Activist African Americans who are constantly screaming about systemic racism, probably acknowledge that Biden is a racist but I really dont think they care. He is a useful racist and thats all that matters. Like the rest of the Democrat party they will endorse the transfer of wealth. To people in the genre of your Sharpton type, that is money straight into their pocket.
Biden they know will also cave on every thing the radical wing wants. They love him because he is weak and malleable. So... everything he has done or failed to do in the past is swept under the rug. What he believes they could care less, just as they gave a pass to Senator Byrd.
Trump however does not get a pass even though his actual policies did or were doing good for the African American communities, he's white, a Republican male and quite a bit brash in speaking so all that links him to slave holders of the last 400 years and makes him responsible when a cop shoots a black person.