aprilp_katje has gone on record as hating; that's because the 'joke' is that Michael has just learned that the pork he eats used to be the pigs his uncle raises.
(Strip Number 442, Original Publication Date, 18 July 1983)
Panel 1: As Danny slops the hogs, Mike says that they sure are big ones.
Panel 2: He then asks his uncle why he doesn't give them all names.
Panel 3: Dan tells him that that would make them too much like pets.
Panel 4: Since Beardo the Weirdo's back is turned, he doesn't see that his off-hand remark about not wanting to eat something he's had a personal relationship with has broken his nephew's brain.
Summary: The 'joke', as I see it, is "Hurr-durr-hurr!! Little kids don't know where their meals come from! HURR-DURR-HURR!!!"