> octopuses will form dominance hierarchies

A dominance hierarchy is not a good argument against abuse of a sentient creatures. Nor is it an argument that a "community" exists. Lobsters and beetles do this as well.

The real and substantive argument against octopus farming is that it won't work. The dollar to calorie ratio will be too high. Even if it does get going it'll collapse in a year. Might as well try farming wolves.

IMHO it's a poor idea and punching bag.