"If you say a modern celebrity is an adulterer, a pervert and a drug addict, all it means is that you've read his autobiography"

This quote by P. J. O'Rourke is an amusing way of mentioning the tendency of modern-day celebs to be overly open about their personal lives. O'Rourke is recommending that if someone makes a declaration about a star being an adulterer, a pervert, or a druggie, it is likely that they have simply check out the celebrity's autobiography. This implies that the celeb has picked to share this details with the public, which the declaration is not based on any real proof. O'Rourke is poking fun at the tendency of celebs to share excessive info about their personal lives, and is recommending that it is not constantly smart to think everything that is stated about them.