#BlackLivesMatter protestors did what they ought to have done at NN15 - following an honored tradition of political protest. Following an honored tradition of getting a disadvantaged and threatened voice heard.

It has worked in the past and it ought to work this time, too - given the extreme circumstances.

The protest wasn't about Bernie or Martin, it was about #BlackLivesMatter.
Bernie and Martin were simply, somewhat cluelessly (like any other candidate in the current slate would have been, if they'd bothered to even be there) there.

IMO, neither were up to the moment. But neither (in spades!) would the other candidates (who were not there) for either party.

Maybe this demo provided a hint that's there's a need for a change of direction, of thinking.

I don't agree with the spin that pins the problem on Bernie and/or Martin, in particular, just because they were the platform speakers.
The spin that excoriates them, for being there.
I don't agree with the spin that says #BlackLivesMatter was intending to cast Bernie and/or Martin as racists or just wannabe racists or paternalistic or whatever, just because they were the platform speakers. Nowhere have I read direct quotes stating that was #BlackLivesMatter intention.