It is an anthropological study, I doubt they care about the effects of cannibalism on modern populations who can lab test jerky Epstein style.

Somewhat similar to how homosexuality tends to spread more disease than even promiscuous heterosexuality. If a pathogen has a high chance of being spread by A performing an act on B and B can perform that same act on C, then a pathogen spreads much quicker than if B is physically unable to perform that act.

Same goes for taboos against eating terrestrial predators. If a wolf can catch an illness from eating a human, people develop a taboo against eating wolves because humans can probably catch it back by eating wolves.