Japanese harvest ships slaughter thousands of dolphins each year, in a certain bay. Some escape. Next year, more olphins return to the bay and are caught, seemingly by surprise?
SO either, the escaped dolphins did not communicate the danger, were unable to communicate, or just didn't care what happened to other dolphins.
In any of those cases, do we have the duty to protect the lives of dolphins? Either they are not intelligent, not communicative, or have no racial ethic that values dolphin life. Why would we?
So this argument isn't 'considering the issue at all'? Then what's it about? Some other issue? Would a personal attack have been more on-point? (sarcasm)
Got it? That's the entirety of the argument. If you'd like to address that argument, great. If you just want to agitate for dolphin right by shouting down argument, then fell free, I'm done.
Dolphins are of course very 'dumb'; its taken years of hard research to come up with any evidence of intelligence, and its all indirect. Why we even bothered? Probably because of their large-ish brain, which turns out is an elaborate visual cortex (ok, sonar cortex, same thing).
They play; they have family units, at least for a while. Is this intelligence? Crows do all that too; many other mammals also.
Caring for humans is anecdotal. My favorite one is, people adrift from shipwreck get pushed to shore by dolphins. This suffers from observer bias - dolphins love to play with floaty things, and push them around. All the sailors pushed out to sea don't tell their storey.
May dolphins be intelligent? Ok, sure. But as they don't have societies, inventions, any more language than many birds, their intelligence is very much more similar to other 'lower' animals than human.
Maybe its a different kind of intelligence? That's reaching, kind of making up things to fit a desired conclusion, but ok. Then the 3rd argument in my original post: its a kind of intelligence that doesn't extend to saving one anothers' lives. If even one escaped dolphin mentioned "I got out of there; all my family are missing, plus two other pods I know of; maybe we should stay away from that bay", we would have fabulous evidence of an intelligent society sharing the planet with us. Observably not happening, so one could conclude (I never said I conclude this, thats your projection) that they are of an intelligence too small to permit that communication. In fact, occams razor damands this conclusion.