You can watch the whole thing here - but the upshot is some old white man is screaming at this woman to go back to her country and she shouldn't wear a Puerto Rico shirt in America.
This is asinine for a couple of reasons.
First - Puerto Rico IS part of America.
Second - The shirt is a Commonwealth Flag. It is the same as a Texan wearing a shirt with the Texas Flag or my shirt with the Californian flag superimposed on the state of New York. It is NOT an independence flag you dumb shit. It is the flag of a United States region.
Third - An old white Police Officer just stood there as she asked for help. Finally other officers came up and arrested the asshole for assault.