I encourage everyone to read Oliver Willis's comments about #BlackLivesMatter and Bernie Sanders. Despite the misleadingly alarmist title, he makes a very useful point about how political progress happens. Too bad he can't do it without lapsing into talking about the Sixties, but that doesn't negate his underlying point.
A couple things to get out of the way. One is that nobody should tell oppressed people the appropriate means of fighting back against the dominant power structure. If #BLM people want to get up and interrupt every speech by every presidential candidate from now until the end of time, it's not our place – whether we're white, black, or any other race – to tell them not to. Clearly being polite and patient has not worked out terribly well for Black Americans. Second, the Sanders campaign has indeed been remarkably tone-deaf on race, resembling a Nader campaign that emphasizes stroking off white progressives and doesn't seem to know how to appeal to anyone who isn't moved by arguments about economic inequality. He deserves the criticism he has received. Finally, I don't believe that Willis's criticism comes from anywhere other than a deep desire to see these issues addressed and to see the movement succeed. He has been vocal and consistent for more than a decade, filling the internet with all manner of useful commentary about the same issues that #BLM has come to represent.
That said, I really don't understand how it's so sacrilegious to suggest that maybe – just maybe – this is counterproductive. By all means, interrupt the hell out of every political figure who isn't paying attention to these issues. The interruption isn't the bad part. The having nothing to say when the microphone is in hand is the bad part. The media and The Establishment have long since figured out that the best possible way to discredit protesters is to stick the camera in their faces and let them talk. The resulting footage gives every American inclined to discredit a social movement the perfect opportunity to do so. It happened with Occupy Wall Street. It even happened with the Tea Party, although their short term influence was considerable.
Nobody likes criticism. Criticism, even when well meaning, usually stings. Often it takes a long time to recognize the value of critical advice. Even if we know intellectually that criticism is intended to help us, we still have a natural tendency to resist. And if Oliver Willis or anyone else can't look at this movement and say "Hey maybe come up with a 3-minute summary of your goals so that when you get the chance to spread your message there will be an actual message to spread, since that will probably accomplish more than extemporaneous word salad," then it's already a lost cause. This isn't even controversial; staying "on message" is demonstrably essential to successful collective action movements.
If someone is criticizing these protesters because they're Rude or because they should be more compliant, that's a load of horseshit. Shrinking violets aren't successful in this game. If, on the other hand, someone has substantive criticism about methods and how likely they are to accomplish one's goals, it might not be a terrible idea to consider those points rather than lashing out at people who want the same thing you do.