
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.
I’ll stand by the position that the Enterprise augment virus arc was an error, and the “explanation” for Klingon ridges is the same one you should use for the bridge of the Enterprise looking like it was cobbled together from plywood and plastic beads. This issue was best left to Worf’s lampshade in DS9 Trials & Tribleations.
It’s really interesting which visual differences humans will accept unthinkingly and which we will demand answers for. The Klingon ridges thing comes up constantly, but I have yet to see anyone earnestly ask why all the characters in Lower Decks have huge eyes and unnaturally uniform coloration, or why hand phaser beams in TOS go so much more slowly than later phasers and why everyone agrees to stay really still while they are being fired.