As a leftie I have no problem with a small radicalised and vocal member of society doing anything. I also have zero problems with MLK and what he managed to accomplish - but I still differentiate between cancel culture and boycotting as a political tool.
MLK was the mouthpiece for an organised movement of people with a legislative aim and a non-personalised agenda. MLK did not 'cancel' things, he challenged at a legal, political and social level. There is a world of difference between what MLK did and what cancel culture has become. On the venn diagram there is likely a cross over point between boycotting and cancel culture, but the former requires organisation, conversation and a clear aim, the latter is simply atavistic herd mentality.
Social progress can be achieved but there is nothing socially progressive about what happened to Justine Sacco in 2013. You've conflated the act of advocating for marginalised groups with the pleasure a gang of primates feels when it rips an enemy apart. For the most part it doesn't work on those people prepared to ignore it. You can't cancel people who don't believe in cancel culture.... what you can do is use it as a weapon to keep your own side in a perpetual state of fear. That's where the political left currently sits.
And yes, as I said.... the alternative plan is legislative change, restorative justice and open conversation. Some of that can be about boycotting, if that's what people want to do - but such a movement needs a figurehead to centrally control it. Were MLK alive today, that is what he'd be doing. Patrisse Cullors-Khan is an ersatz copy. It's hard to see MLK ditching a political movement to finish a book and deal with Warner Brothers whilst being 'a marxist'. If the left is prepared to centralise around a single figure then it might do the sort of political change you're after, but the left is too busy tearing itself apart and picking off its own recalcitrant children to stand any chance of that. What the US needs is a decent socialist - and they have one (Bernie Sanders) but he's got zero chance of getting in because despite being 'progressive', most US citizens are economically right wing.
