
It’s because citrus at high concentrations kills earthworms. Citrus in compost in normal quantities relative to other compostables seems to be fine, but you shouldn’t be trying to compost a huge pile of just pulp and orange peels in your back yard.
As for why this worked here, I’m sure there are a whole lot of things that aren’t earthworms living in a formerly rainforested spot in Costa Rica which can break that stuff down over 15 years.
Reading the caption before seeing the image definitely weakened today’s comics for me.
Captions of Far Side comics are often effectively punchlines, clarifying whatever weirdness was drawn in the comic. Reading the words and then seeing the image feels disjointed, and loses a lot of the “punch.”