"Does Humor Belong in Music?" MPI. $24.95. Frank Zappa deserves credit for standing up to the censors in D.C., but this creepy, oppressive, one-hour concert tape is a far less admirable gesture. Anti-gay, anti-disco, anti-Reagan, anti-video, anti-rock 'n' roll--Frank doesn't care for much of anything except himself. Trying to pass off a parade of adolescent sex hang-ups as iconoclasm, the pre-haircut Zappa rigorously avoids both cliches and hooks in the music and offers a smug, myopic put-down of the L.A. rock scene that we might buy if he had something better to offer. He doesn't.