Nothing new or evolutionary about that, squirrels have been eating meat since squirrels began. If these people spent enough time in the woods to know how the natural world works they would realize that it's just something squirrels do. A number of times I've watch gray squirrels and fox squirrels jump on a bird, kill it and start gnawing on it. I sat and watched a gray squirrel attack the hatchlings in a robin's nest. It ate the brains of all three. Didn't touch any other parts, just the brains and left the dead bodies in the nest. Flying squirrels regularly eat carrion. Also on two occasions I've seen deer eat fledgling birds that were out of the nest learning to fly. An animal will do what it needs to do to get the protein it lacks.