I'd like to see some cultural connections that he thinks proves they had "battle rage" cannibalism. I don't recall them being culturally more violent than, say, your average American. In order to prove a connection I would like to see what folk stories he thought promotes this idea (legends and so forth) and which of their ceremonies promotes coming home with the dead to eat them.

...and whether they ate their own dead or just enemies.

Anthropologically speaking I'm not convinced but I haven't seen his sources. Can anyone dig up a paper?