Of course someone can exhibit controlled anger.

Of course someone can exhibit controlled anger. That’s irrelevant to this argument, though. The point here is that Peterson ignores the distinction between anger and assertion, in order to make his point, but he’s wrong to do so, and to support that objection I only have to show that one can sometimes be assertive, or even behave angrily, without feeling anger. The existence of something called “controlled anger” wouldn’t contribute anything one way or another to the logic of that argument.