I think all the crap humour and blatant silliness is part of the point, FWIW, although I'd have trouble articulating how. If everything was serious and plausible they'd be much weaker books...
This bit at the end of Foucault's preface to
Anti-Oedipus seems plausible with regard to Pynchon too,
"It could even be said that Deleuze and Guattari care so little for power that they have tried to neutralize the effects of power linked to their own discourse. Hence the games and snares scattered throughout the book, rendering its translation a feat of real prowess. But these are not the familiar traps of rhetoric; the latter work to sway the reader without his being aware of the manipulation, and ultimately win him over against his will. The traps of
Anti-Oedipus are those of humor: so many invitations to let oneself be put out, to take one's leave of the text and slam the door shut. The book often leads one to believe it is all fun and games, when something essential is taking place, something of extreme seriousness: the tracking down of all varieties of fascism, from the enormous ones that surround and crush us to the petty ones that constitute the tyrannical bitterness of our everyday lives."
That and him having a goofy sensibility and that being just how he writes.