Further Understanding my bias-- a surprising finding

While I have been reading up on cannibalism, I've found it incredibly hard to view the phenomenon in an unbiased way.I understand cultural relativism but at the same time feel that there are some things humans just shouldn't do. In order to truly understand the act, I think it's important for me to get past my own bias. But at the same time, should I judge the Māori of the past for eating human flesh? Should there be at least some basic human standards that bypass cultural relativism?

It seemed like a question I would never answer, but as it turns out, I wouldn't have too. I stumbled upon an interesting article on ABC.net that, in a way, defended cannibalism. It didn't exactly defend it, but it explained that the presence of certain genes could only have come about when cannibalism was taking place. They found this gene in people all around the world--which means that cannibalism is something that people on all of the continents did at some point. This made cannibalism seem more normal, if one could call it that. The idea that cannibalism was a world wide phenomenon, and not just something a few groups of people did, made it slightly easier to get into the mind's of the Māori that i was studying. It did ,however, bring up another concern: My latest finding (that cannibalism has taken place worldwide) has made me question how much I really know about cannibalism. It did seem likely that the Māori did it for more than just revenge, or that it at least goes much deeper than that.