Comedic music: A true music?

I've been thinking and listening to some off the wall charts by some famous musicians and I thought: Is this type of music considered a true form of music? I think of all the bands I like that do nothing but make music for comedy purposes. Tenacious D, Stephen Lynch, Weird Al Yankovich, Frank Zappa are a few people to name that have succeeded at becoming infamous when it comes to making music that is otherwise "subjective" to listeners. So my question is to you, do you think that this type of music should be called music, and why?