|2008 Barack Obama||75.3%|
|2008 Hillary Clinton||23.8%|
|2016 Hillary Clinton||78.7%|
|2016 Bernie Sanders||21.1%|
Bernie may have hoped to reignite the voter coalition that carried Barack Obama to victory over Hillary Clinton. He may even have made inroads against Hillary among young white women voters, but he got a cool reception from a key constituency. Minority voters did not Feel the Bern, or they felt it in a negative way. You can see it on the national map too. Bernie just couldn't attract the states with large percentages of black voters across the South.
2008 Map (Barack in purple, Hillary in yellow):
2016 Map (Bernie in green, Hillary in yellow):
Why? Bernie supporters certainly noticed, and had explanations - the most vacuous and perhaps insulting of which was that minorities were "unfamiliar with Bernie Sanders."
This lack of minority support came as a great surprise to the socialists supporting Bernie Sanders. A great many minority politicians and intellectual figures are socialists, why not the minority grassroots? It made some Bernie supporters downright angry that they weren't getting the minority vote.
My theory is simple: minorities aren't socialists. For African Americans particularly, slavery was the ultimate form of wealth redistribution, Jim Crow its inbred cousin. And why would you favor a system of government that propounds that the majority can tax and redistribute if you're are a minority? I ask this from my libertarian sensibility, the minority of one.