I'm surprised to see that the leap in this case appears to be extending moral consideration to beings other than oneself.

I'm sorry, I'm being unclear. I'm not arguing that person X should maximize their pleasure and minimize their pain and not care about anyone else. I'm arguing that person X should find a different utility function than pleasure minus pain (and that includes their own).

ceteris paribus, better to have suffering than not to.

I'm very glad you included this phrase, because that's where our disagreement lies. I don't think ceteris paribus is an option in most of the cases I'm considering. For example, the positive effect of a rite of passage scales with the amount of suffering undergone during it.