Uh, it wasn't milk, it was meat, dude had eaten meat and they smelled that and yes wasted him. But if they killed anyome with milk on their breath they'd be dead already as a species.Aslan and Vargr appear to both eat defeated opponents, and everyone likes roasted K'kree except the K'kree, who are out to exterminate all carnivores, and realistically, all other life except K'kree. After all, other herbivores are competing with the K;kree for food.
As in another thread, I believe that Aramis said that in one of the modules, a K'kree killed another sophont, I think a human, because it smelt milk on its breath. That pretty much makes the idea of human servants for K'kree a total non-starter for me. Killing lactation human females is going to rapidly eliminate human slaves.
And are you ready to swear with complete and absolute certainty that canabilism is not still taking place on Earth?
As to the Aslan and Vargr eating other sophonts, uh..no. I mean maybe there are some Vargr out there who might but on the whole it isn't mentioned in any canon source I've read.
Also, no one who wants to stay out of prison should be eating sophonts, that is criminally insane behavior and pretty sure most sane societies will prosecute that (excepting only emergency situations and even then the eaten had best been dead of other causes or it might get down to murder).
Yeah, it happens here, trust me I know, but then the authorities put that dude in prison. And as to the low tech societies it wasn't as wide spread as people think, it happened but as you'll note not in the first or even second world nations.