The back story is, from what I can gather: the Police officer was arresting another (Black) man for jaywalking across Martin Luther King, Jr. Boulevard. Some people on the street objected and approached the officer (albeit somewhat violently). There was a confrontation, and as you see in the video, when the situation got heated, the cop punched the woman in the face.
The main question that's come up is: is this racist? The officer was clearly outnumbered, and the women were somewhat violent and confrontational. Should cops be allowed to use force in the face of violence on the part of citizens? Was he "protecting himself" or "controlling the situation?" Was his behavior in line with his duties and responsibilities as a Police officer?