They had no probable cause to arrest or harass the man, so he should not have been forced to resist. Just because I guy has a badge that does not give him the right to put his hands on anyone.
How do you know they had no probable cause? The article said the guy was known to sell illegal cigarettes. Whether he had broken the law or not is up to others (judges, juries, etc.) to decide. But if a cop says “You are under arrest,” you have no right to resist. To do so is worse than stupid, it is criminal. The time to contest the legitimacy of the arrest is NOT out in the street.