It is possible that some of our now extinct sibling species also weren’t fazed that much by a dead fellow. It depends on default settings of a character and may be orthogonal to subj. The same stands for humans, some cultures celebrate the death.
This is not my experience at all. And I’ve been quite shocked by what farmers I know have told me about how pigs treat injured brothers (eating them alive). And yea, they weren’t starving.
I am basically an animal intelligence/emotional range maximalist but that doesn’t mean they respond the same way we do.
Well, I can't speak to what conditions your pig farmer friends keep their pigs in, but none of the dozens of pigs I've ever raised had ever shown any kind of inclination towards cannibalism. Sows eating their own piglets is the closest I've heard in natural conditions, but there is probably some deeper evolutionary reason behind that and not just like "oh nice, an easy meal!"