This is unfortunately rewarding poor behavior with extra attention- it's teaching people that they get better service when they are rude.
In a face-to-face position, this might be a good coping strategy where the confrontation is temporary and unavoidable.
On the web, it's best not to engage with rude users at all, since they will continue coming back and learn to expect attention from negative behavior. Try to only engage with polite and positive users.