A quick read on Wikipedia says the Bati is a Warrior Caste, but I think there was a history of cannibalism post battle for the Fijians.
There's a history of cannibalism basically everywhere, in fact it's so ubiquitous that culture's without some history of cannibalism are the unusual ones. It's one of those quirks of human behaviour that polite society and academia likes to pretend is overstated or even didn't really exist, more myth than reality, but is actually a common behaviour, especially amongst hunter gatherers.
The only reason cannibalism is more associated with the PI's than some other places is because it was still a common within recent times in most pacific cultures, even within living memory, and in New Guinea's case (both West Papua and PNG) it's a very rare, but still extant, behaviour.
There's absolutely no chance that the NRL, or any other serious sporting organisation for that matter, would ever allow one of their teams to be called the Cannibals, nor was I seriously suggesting that they should be. The fallout would be f**king hilarious if they did have to balls to pull a move like that, and that merch would be an instant buy even if it was just for the laughs.