Free Republic

  Garry Trudeau, creator of ''Doonesbury'', the only comic strip to win a Pulitzer Prize, says, ''If someone isn't mad, I'm probably not doing my job.''    His latest collection, ''Peace Out, Dawg! Tales From Ground Zero ''(Andrews McMeel, $16.95) continues his tradition of publishing an ''anti-blurb'' on the cover. ''Insults are funnier than accolades,'' he says.    The anti-blurb comes from the ''Opelika-Auburn ''(Ala.) ''News'', which in November, after ''Doonesbury'' resumed ridiculing President Bush, dropped the strip ''voluntarily to honor our national resolve.''    The editors, among others, were offended by a strip in which an aide tells the president...