“Do not answer a fool according to his folly, or you will also be like him. Answer a fool as his folly deserves, that he not be wise in his own eyes.”
Sometimes you need to ignore a fool, for your own good.
Sometimes you need to answer a fool as his folly deserves. And what kind of response does his folly deserve? Mockery, scoffing, and scorn.
For his own good, there is a time for mocking the fool, showing him the folly of his foolishness.