Read A Letter from Birmingham Jail and them come back to me
i didn't read the entire letter, only up to about the 9th or 10th paragraph, after which i decided to just skim through and look for him admitting he punched people he disagreed with
didn't find that but what i did find was a whole lot of "i advocate nonviolent tension" and "channeling that discontent into creative forms of nonviolent protest", which aren't direct quotes but are basically what he said
so if you'd present mlk saying "i punch people that do not share my opinions" or some stuff like it that'd be cool but if not i'm just going to go with my first assumption that mlk did not in fact go around punching people himself in an attempt to get his message across