I'm not a man, so I can only speak theoretically. However, I believe that one of the premises of Primal living is that it makes the hormone balance better. If you've not have any "anger" urges since Kindergarten, that makes me wonder if you've also had an imbalance of testosterone all this time? I'm just saying that my personal observation is that men with low-testosterone tend to be conflict-avoiders; they self-report that they rarely "feel" angry. Teen-age boys who get "normal" amounts of testosterone often want to fight everything that twitches, until they learn how to control those urges.
So maybe what is happening here is that Primal living has finally gotten your body's testosterone into a balance/level that you are feeling those urges for the first time in your life?
btw -- I think that's a good thing. And yes, my suggestion would be to channel it.