When the Founding Fathers drafted the Constitution, they didn't exclude law enforcement officers from the right to free speech. So we do not have to remain silent while the fringe voices a cacophony of anti-police rhetoric.
Cops are being punished for activities that they participated in while off duty and while not identifying themselves as officers. So one has to ask the questions: What is an officer permitted to do off duty? Where are the red lines? And at what point do officers lose their First Amendment rights?
You must act with considerable discipline and restraint when loudmouths try to demean and upset you with offensive language and gestures.