I cannot speak for the Floyd case specifically, but I cannot ignore how often it happens in the U.S. that a white cop is extremely violent to a black suspect, and then the appearance of racism cannot easily be ruled out, and that black people are fed up with that is only natural and that they are angry about it too, and that they speak out is a right they have. This goes further than just the person of George Floyd. I lost track of counting how many times this has happened. So just asking if you knew him in person, is NOT the correct argumentation!!!!! The question is actually pretty stupid and a sign to ignore the systematic issue at hand and a bit offensive even.
Of course, it does not give anybody the right to destroy a car, vandalize private property in general and looting shops etc. etc. etc. and therefore make people victim who were not involved in the entire matter and I cannot ignore either how that happens after every case. Those reactions are actually quite stupid too. If you want to Afro-American society to be treated equally to the non Afro-Americans, the least you can do is at least show you are better than them. Vandalizing, looting and making people (who are not involved) feel threatened is not the proper way to do that. In fact, it will only "help" racists in saying "See there, we were right all along", and that's the last thing you want to happen. Am I wrong?
And to come back to my earlier statement. Even if George Floyd was an acquaintance of yours, vandalizing a random car or vandalizing in general and looting is NOT the right way to go.