We have different concepts of normal.
Consider, violent situation, battle, your emotions and adrenaline at the highest levels, your lover
is murdered before your eyes stupidly.. Would you lose it like Harry did? Or collapse in a puddle of
grief? Or say,"oh my, he killed her, call a policeman to arrest him." All are possible normal reactions here, I am not saying his reaction was a thought out thinking reaction. It wasn't. That is the whole point, once Butters got Harry back to thinking sanely again, and yes, it took a lot because Harry is a dangerous powerful person, Harry was ashamed of his reaction. However not at all a shock that he reacted that way, nor does it make him a bad person for reacting that way. If he hadn't been stopped, yes, then the complexion of his reaction changes. But he was, and he reverted back to the basically good man that he is. Because he wasn't fully responsible for the emotional violent response he had to Rudolph stupidly and deliberately murdering Murphy before his eyes.
Wanting to kill the man who just killed the woman you loved is quite normal. Not doing it because of other considerations is also quite normal.
But your primary instinct is to kill him. The rest is a result of a civilization process that is sometimes so successful that you have lost some contact with your primary instincts.
That is ok. Living with so many people would be impossible otherwise.
Yes. And why we are very lucky when we have friends like Butters who will try to stop us in those
moments from doing something we'd really regret later once we calm down.