I think its been discussed more in other forums, and it is way off topic for this forum.
Regardless, my final post on this thread, yes, I'd say Dolphins are smarter and feel more more than oysters, and oysters feel more than insects who feel more that bacteria, but where will it end so that that becomes permissible food item?
If one says veggies, another can say chicken. If one is trying to create some ethics or moral truth about feeling and intelligence needed to be food, well, tell it to the Eskimos, Mongols, or Bedouins.
Finally, I'm more interested to know if an Eskimo wanted a Rigol 1052e and in knowing what they'll use it for, in a place like Barrow, Alaska.

Meat comes from "animals" [that is, anything that isn't a plant], its just a question of how one goes about 'harvesting' it. In the wild, its not done humanely, whatever that means, and its easy to see if you study natural history more or if not so inclined, watch any of BBC Attenborough shows. He won't sanitize it like Discovery channel or Disney will for the sake of 'family time' or the 'Finding Nemo' generation.
Some predators at least lions, tigers, and even cats, give the prey the coup de grace before dining, compared to these folks. Begins at 30 sec from the start, you can see the terror in the prey's eyes.
I'm not convinced.
Fair enough, in nature the last minutes of the prey animal's life may not be very pleasant but at least it got a chance to live properly in the first place, unlike a poor battery hen reared in a human run farm.
Then there's the case of which animals suffer more than others, you can hardly say a brainless oyster has the same mental capacity to feel pain and suffer as a dolphin.