Biden wrote the 1994 crime bill that packed our prisons with minorities, a bill which if it had not passed would have allowed the Democrats to win every election. All of the disenfranchised felons that were stopped from voting is one of the reasons Gore lost Florida.
And the fact that the 2016 candidate was the wife of the man who signed it in law might have had something to do with minorities not turning out.
That's why they supported her heavily in the primary, am I right?
I don't have the time to go grab numbers right now, but my recollection is that primary turnout is only a fraction of GE turnout. So yes, she would've gotten high minority support
for a primary, but still gotten less minority GE support than one might reasonably expect from a candidate with D after their name. Sexism and a sub-par campaign operation could also account for some of it.