hoax
Explanation
The Joke
A man muses, "I wonder if moon hoaxers are as pessimistic as they are." He then proceeds to lay out the moon-hoax conspiracy theory's implications in a way that actually makes it sound incredibly optimistic about human capability: "We haven't put a single man on a fake moon sound stage since 1972, partly lack of budget! We used to have a massive fake reusable launch vehicle and used to fly to a fake lunar station with it. The process instruments we use could've been faking a Mars landing by now." In other words, if the moon landing were a hoax, the conspiracy theorists would be lamenting that our fake space program has actually declined -- we used to be so much better at faking space travel than we are now.
The Humor
The comic cleverly inverts the usual framing of moon landing conspiracy theories. Normally, hoaxers are seen as cynics who distrust government and science. But Weinersmith points out that if you take their theory seriously, it actually implies something even more depressing: not only did the government fake the moon landing, but it can't even muster the resources to fake one anymore. The conspiracy theory, taken to its logical conclusion, becomes a story of institutional decline -- we've lost the ability even to produce good hoaxes. The humor lies in this unexpected reframing, where the conspiracy theorist ends up sounding like a nostalgic space enthusiast mourning the glory days of NASA, except everything he's mourning is fake.