Ancient peoples who lived on small islands had a problem controlling their population to match the available resources. A good way to do that is to capture their enemies, enslave the women and children, and eat the men. Problem solved. Repeat as necessary. It wasn’t fair and it was racist, but life was a bitch back in the day.
The Karankawa tribes lived along the Texas Gulf Coast. Fierce warriors, bowmen, hunters, fishermen, etc., they were also cannibals. Tribe supposedly went extinct by 1860.