I really don't get the dismay. Sheep, cows, fish even, feel pain and probably feel emotions. So why stop now? It's such an arbitrary line.
Speaking personally, I wish we'd stopped sooner. I'm not here to say all meat is bad and everyone should be vegan, but I don't feel it's out of bounds to be dismayed that we're expanding the barbarity to new animals that clearly appear to have a form of higher intelligence.
I'm not the arbiter of truth on this, but I'm sad when I see pigs in factory farms, and I'm every bit as dismayed to see us expanding this to cephalopods just the same as if we expanded this to domestic canines.
Then, it's easy to grow a conscience when confronted to trendy newish things like so-called sentient animals we never really ate before.
This is a good thing. Growing the masse's consciousness through new fads and phenomenons is a great way to create cognitive dissonance that contribute to changing old habits. Even if one will always encounter resistance to change.
However, the current consensus is that consciousness/sentience is a gradient. The higher the sentience, the higher the ability to experience (anything, including pain and emotions).
We believe humans to be more sentient than octopi, which are more sentient than cows, which are more sentient than fish, which are more sentient than yeast.
We might be wrong of course. It's probably impossible to even ever find out. But no one cares about hurting yeast.
They can do basically anything that a bird does, but underwater, and also a lot of tricks that we can't do.
There is not a single bird or mammal crystal transparent, or electrical, or bioluminiscent, or that could change their color at will in seconds. If I remember correctly, the vertebrates with the biggest brain/body weight ratio, or the fastest movement registered, are fishes.
They have centuries and centuries to settle the question while rearing and killing billions of human beings each year.
N.B. The price of baby meat is higher because it's more tender or whatever.
Now ask yourself if the level of sentience that develops in this environment is satisfactory. Is there even a chance of developing thinking matter that can have a debate about ethics?
Fortunately we could teach this aliens about the delicacy of octopus farming.