A: "Heresy"??? Sorry, I don't get it. (Hopefully a bit of an in-joke.)
B: There's also taking everything as a joke, which is at least as annoying as taking everything too seriously. What I got from the piece is that that's how people, either intentionally or by just being forever thirteen-year-olds, are trying to dismiss "This satire of fascism has turned into straight-up propaganda for it". Sure, that's kind of hilarious... But also serious enough not to be just laughed off.
(it's not just 40K; Cleese had to explain Fawlty Tower's use of the unsympathetic comic foil to people who took them entirely too literally)