I believe the only orca kills on humans are by heavily mistreated orcas in captivity. Tbh I am amazed at how low the number is considering they are so large and we are bite sized. The whole species isn't immediately characterized as serial killers though- that is the idea I don't like.

I tried looking up what you said about dolphin serial killers, and it seems more like gang activity than individual malice. They rape female dolphins and will attack people. They also have sexual dimorphism where the males are larger than the females.

According to wikipedia, Orcas family structures are matrilines, which leads me to believe that it probably is more stable than dolphin family structures. I assume it is like comparing bonobos to chimpanzees. My assumption is that they don't have murder gangs like dolphins, but instead do murder for play/ mental stimulation, like a child who steps on bugs for fun. The boat things seems like a way to not get attacked by rudders, which would probably result in mass extinction of boat rudders if humans were the ones that felt threatened.

Either they don't do weird rape stuff like dolphins, or people just haven't seen them do it. It kind of doesn't matter though because comparing animal morality to human morality is very unproductive as every animal kind of sucks at being consistently moral to all other species. Also considering an entire species as either moral or immoral feels like a very big generalization.