I think this is disingenuous.
In the first primary debate, Bernie said Black Lives Matter very openly. O'Malley had to beat around the bush and apologize for his atrocious criminal justice record before saying those words, while Hillary shirked the phrase.
That said, Hillary Clinton was definitely more attuned to the needs and concerns of black communities than Bernie Sanders. Race was his most dangerous blindspot, and so-called progressives who think combating white supremacy is a distraction from "real concerns" are racist. Whenever another Bernie-style candidate emerges, they must work
much harder to understand the various manifestations of structural racism and offer stronger policies that respond to the specific concerns of black people. Non-black Bernie fans who oppose this are selfish phonies who will jump off the liberation wagon as soon as they get their free college and universal healthcare.
While the farther reaches of the radical left are very good at explaining and combating white supremacy (thanks to the great participation of people of color within socialist orgs) the reddit/Young Turks wing of the Bernie movement is anything but. SandersForPresident types are ignorant of black struggles at best, and expressly racist at worst. There are imperialist and white supremacist tendencies throughout all sides of the Democratic party and they need to be stamped out immediately.