Just because you hear some Black people say they don't like Joe Biden it doesn't mean what you think it means. Or what you would like it to mean.
Not every Person of Color voted for Obama either.
Believe it or not, not every black person votes Democrat.
Nor every Latino. Or Asian.
There are a few confused people, and people that consciously go against their own ethnicities best interests, by voting Republican. they're called sellouts or Uncle Toms.
But they're not enough to make a difference. Just like with Drumpf's die hard shrinking base.
You're not going to change the minds of the die hard Maga cult that would rather waste & send him $35 for another Mug or a Shirt made in China than to put that towards something that is actually useful for themselves.
And you're not going to change the minds of dyed in the wool Democrats that would vote for any Dem just to be able to sleep peacefully at night knowing they won't wake up tomorrow worried that The Potus sent a Tweet threatening N. Korea with Fire and Fury when he's not giving a Foreign Enemy like Russia Carte Blanche to seize & take whatever Sovereign Country they want today.
It's the voters in the middle of the road, the moderates, who are going to decide, and really vote for the more reasonable and less vulgar candidate.
Because they also want a traditional President who's quiet and does his job and doesn't yell at anybody or boast about being the best or about being a sacrificial Martyr for you. They don't want the Loudmouth self serving extremist who brings Play doh to Lousiana Flood Victims.