There's a difference, though, between being somewhat ignorant of systemic racism and the secondary consequences of your actions and being an outright racist and race-baiter. Yes, certain things that some older Democrats supported, like various crime bills, absolutely had negative effects on the black community and they need to own that. But that's different from being intentionally racist.
If you support Biden, you're supporting someone who has in the past shown a problematic lack of understanding of racial dynamics and how his policies might exacerbate it, but at least someone who isn't looking to screw over the black community. If you vote for Biden, you hope that he's smarter about those things now.
If you support Trump, you're supporting someone who in the past and present has directly engaged in racism, has encouraged other racists, explicitly and implicitly, and has directly blamed the problems in society on black and Latino people. If you vote for Trump, you're tolerating that because it's not like Trump has suggested he wants to change his approach.
I think there's a pretty huge divide between those two things.