This is kinda the plot the later Callahan's books by Spider Robinson. Man-eating aliens who believe the only ethical way to slaughter is to trick the meat into slaughtering itself, and so they infiltrate humanity to encourage that.

I’m pretty sure that if there's an intergalactic rule like this, coercing species into being dumber would also be against the rules.

That would surprise absolutely no one.

Against the spirit/intent of the rules, probably, actually against the rules dubious.

The aliens should consider changing the rule to anyone with a financial value that has a z-score of 2.33 on a bell curve relative to the rest of the world's population.

Given the aliens have a big appetite and understanding that this would eventually wipe out the human race, perhaps limit the numbers of humans that can be eaten to the birth rate of humans so that they create a sustainable supply of food.

Eat the rich!

being 8 times dumber than someone does not mean the other person is 8 times smarter than the other.

1/8 of the smart is what the alien is looking for.

Make A Galaxy edible Again!

How to Serve Men is a propaganda book.

Nobody said the aliens were smart.

yes doctor that's the spot