I think the true conversation there got derailed by semantics. Clearly he feels anger but what I think he was asking was if it is healthy to always shut it down and internalize it. In my opinion, the answer to that was a resounding “no”. By not dealing with that anger, even when it’s disguised as “feeling dumb” (self-deprecation or sometimes even self-hate) or frustration, he has allowed it to fester, take up emotional real estate in his mind, and always be there waiting to bubble up or straight up burst when something seemingly unrelated triggers it.
I think Garnt was on the right emotional track originally. He intuitively knows that he has shit he should deal with rather than internalize. This is why I do not recommend taking the words of your therapy as gospel. Ultimately, if you are able to be self aware as Garnt seems to be, you will know you better. Therapy is a way to guide you towards the answers you seek or didn’t even know you were seeking. Therapy is not there to give you the answers. Maybe, hopefully, it is there to help you ask better questions.