To make the parallel between Priscilla and Paul correct, you would need to add that Paul has been genetically engineered (or something) so that we know that his greatest desire and sole purpose of his life (to himself) is to be eaten--it's not just some weird mental illness. Paul is not a normal human; he's been altered.

And then the reply is, I think: Oh, god, please don't! We humans have enough trouble not killing each other when we don't want to be killed; our moral intuitions are barely up to the task of avoiding that. We can't handle bludgeoning our intuitions with the complexity of humans who want to be eaten.

Then we could come back and say: Okay, whew, we're not going to do this to create Paul--who genuinely doesn't need help, but is very unlike most humans. Should we be doing it to Priscilla? Hmmmm. Hard...to...tell. Not much clarity there. (Arguably chickens already are trending this way.)

What if we made Paul have to swim up a river to spawn, but in so doing he would die--but it was the focus of his life and the only way he could reproduce? Should we, in our horror, find a way to save salmon from their parallel fate?

What if we made Paul desperately want to fastidiously watch over his children with such intensity that the effort killed him when they were young (but they had an amazing, unparalleled upbringing until then, and neither they nor he minded that he died). Would we then save octopuses?

The reasons the parallels don't provide us with much insight is because we shouldn't be doing this to Paul in the first place. Our moral intuitions object: that's not normal; leave Paul the hell alone.

If we assume that we did not leave Paul alone, we are still feeling the that's not normal intuition, which disrupts our ability to think about the hypothetical scenario while fully accepting the premise as given. Cristobal de Losada has, I think, successfully risen to the challenge of thinking this way, but I think the deeper point about this thought experiment is quit experimenting on poor Paul!