People don't have to be nice to each other. On the other hand, if they aren't nice, they should expect reciprocal treatment. Then he goes into a back room. The ensuing fight scene is perhaps one of Jackie's best. If the words aren't intended to offend, as one may presume in cases where they are used by those sharing the character trait being demeaned, then the intention is often to identify a shared burden.
Political correctness is bad when it is enforced by ostracism, force, or fraud.
It is silly when it is used by otherwise sensible people. On the other hand, for Kevin to object to the words being used is just another use of free speech. On the other hand, if they aren't nice, they should expect reciprocal treatment.