I don't believe that's the case for the orcas in the article. I used to live in Eden, and they have a legendary reputation there, going back well into pre-colonial history. Killing them would be sacrilege. That's not to say that some weren't killed, but not on that scale.
I see, that makes sense. Perhaps primed by the article talking about interspecies cooperation I didn't imagine they would not only compete for food but steal it.