There is nothing new about farming and eating predators. First, anyone going to a coastal seafood market will see the shelves full of amazing predatory animals, followed by opportunistic (predator/scavenger/grazer) ones. Second, and from a western society perspective, some of our star farmed fishes are clearly amazing predators, like atlantic salmon, but also sea bass or Gilt-headed breams (note these two predators have been "raised" since ancient times, at least from the old days of the Roman empire), widely eaten and farmed along the Mediterranean shores.
Here the main argument I see (and I have seen in the past on this topic) is on the side of industrial farming, and what is going to happen. It is a reasonable concern So far, it is unknown how it will results so in my opinion it should be tested. I won't increase my octopus intake, but if the project is not as apocalyptic as pointed out by some people, and the quality is good enough, I may switch to captive.