It is a mystery to me when being rude and calling people, whom you do not even know, names has become an acceptable practice. It is so commonplace that place that people seem to have forgotten how damaging it can be.
If the goal is to erode someone’s self esteem and make them feel worthless, then keep up with the derogating, insulting and name calling. It will hurt them. It is doubtful that the perpetrator will get any true benefits from the bad behavior.
Gratitude for karma.