ETs eating Alaskan homesteaders is not cannibalism.
We resolved that issue way back in the early days of the MOAB when freds (an ET species) attempted to eat khandu. Freds eating humans (and khandu is purported to be human) is not cannibalism. Freds eating freds is cannibalism. Humans eating freds is not cannibalism, though why anyone would want to eat freds, who reportedly taste like aluminum foil, is a mystery.
But I suppose anything is edible with enough Tapatio sauce on it.