There's no comparison between what the Niner's back-up qb is doing and Dr. King. Dr. King had an actual message that he could present to the people and the government and he was a humble, unifying force not a misguided attention seeker.
A humble unifying force who was detested by probably a majority of his fellow Americans, and only after his death did some (but by not means all) of his detractors change their tune.
I don't know if a majority detested him. There was support for his ideas amongst more than just minorities and even the prejuiced people i grew up around who had no issue saying hateful things spoke of him with respect.