Yeah, they love the 1950s. Women and blacks knew their place. Women in the kitchen, blacks keeping quiet and getting lynched if they got uppity. Queers and what not just didn't exist, or were imprisoned/hospitalized and/or shunned.
I know this will fall on deaf ears, because your minds are made up about how hard your life was growing up, but black people in many ways are treated as second class citizens to this day in the United States. Police harass them, stores treat them differently, cabs won't pick them up, and they were denied good jobs, educations and places to live. Even poor white people are typically better off because they don't face many of these same situations. And, yes, there are justified cop shootings against blacks, there are a massive number of police interactions that end violently far too frequently. They treat them as animals or the "other." The cops put on deadly chokeholds onto black suspects, or shoot unarmed people. And they are rarely face punishment even in the most egregious situations.
And whoever said that they are revolutionaries, you're damn right. They want to change a broke and corrupt system. They are not calling for violence, but they are demanding change. They want to educate people and help end violence against black people. And, by saying black lives matter, it doesn't mean others don't. They just want to be treated as equals and have the same rights and treatments as anyone else. And, despite the GOP only knowing one MLK quote about character over colour of skin....that hasn't happened yet, and we are a looooong way from that.
Finally, to the person who said MLK would be rolling over in his grave. You are so wrong. King would have been marching with them. He would be leading the charge. Read some history books. He said a lot more things after 1963 and before he was assassinated. That might help you understand how wrong you are.