Just as the first step in treating a disease is coming up with a correct diagnosis, the satirist believes that the first step in ameliorating a social ill is naming it accurately. I would distinguish true satire from such related idioms as parody and burlesque. Douglas Adams's Hitch-Hiker's Guide to the Galaxy and Terry Pratchett's various buffooneries offer their readers abundant joy, but I wouldn't call them satire. Adams is primarily out to delight us with his marvelous send-ups of genre tropes. But the satirist isn't terribly interested in delight, certainly not in delight for its own sake.
Satire is a deadly serious business.
It's funny only by default. We satirists use humor primarily to get the reader's attention. Humor is the wooden horse that lets you sneak your agenda inside the walls of Troy. A writer with whom you're often compared is Kurt Vonnegut. I consumed heavy doses of Kurt Vonnegut while composing my first two novels, and I'm sure that some of his attitudes and sentence rhythms crept into my prose.