You're getting needlessly defensive. There isn't that implicit assumption. It was simply speaking of the double standard of "humane" people have of land animal

You're getting needlessly defensive. There isn't that implicit assumption. It was simply speaking of the double standard of "humane" people have of land animals vs fish. And how that standard might not actually be justified - in other words a cultural myth. It even said "For aquaculture, at least, we have some control, and I suspect the movement will begin there. I could envision having Atlantic salmon, say, from a farm, that has some sort of humane treatment approval — free-range, or whatever — for people who are willing to pay a little more for some animal that's been treated reasonably well."