It’s the northern state with the second-highest black population. I don’t know why it being solidly D would be surprising. Ohio would be solidly D if it were 21% black, too.
This is another example of the typical fallacy of only thinking about the white voters in a state.
Actually, Trump would have won Ohio if the electorate was 21% black. The electorate is already 14% black.
Also, Mike Castle is an example of a Republican that won statewide in Delaware many times... until he lost the primary to the witch.
Ohio is only 12% black, and I guarantee you the electorate is closer to 11% black (under-18s are disproportionately black, around 18%, and it's pretty obvious from precinct results that black turnout is slightly lower than white turnout, other than in 2008-2012). Don't care what an exit poll says; they're largely bullsh**t reverse-engineered to match the final results such that the crosstabs are totally valueless.