"Satire is a sort of glass wherein beholders do generally discover everybody's face but their own, which is the chief reason for that kind of reception it meets in the world, and that so very few are offended with it." Swift
The satirist is thus a kind of self appointed guardian of standards, ideals, and truth; of moral as well as aesthetic values. Satire is a kind of protest.
Ronald Knox likened the satirist to a small boy who goes about with a water pistol charged with vitriol. He also suggest that the satirist is a kind of spiritual therapist whose function is to destroy the root causes of the major diseases of the spirit, like hypocrisy, pride, and greed.