Bouie's twitter feed has been really, really good during these primaries.
It's understandable why kids just getting into politics would make the mistake of thinking a state's primary electorate = its general electorate. And losing political campaigns tend to say silly things, especially with these drawn-out primaries (see Rubio this time, Hillary in '08).
But if you're a prominent person on the left half of American politics, in 2016, and you find yourself making an argument that implies black people's votes are somehow less valuable than other votes, you gotta stop. Seriously. Just stop.