so i can hit my bird so long as i am not angry while doing it ????

so if i break its bones by hitting it thats ok so long as it wasnt done in anger?

yes we all have instincts, but it is not natural for your first response to be harming something smaller and defensless, in fact it is instinct to protect it not harm it.

your theory holds no water, sorry.

you are free to believe it and you can try to justify and sugar coat this persons actions all you want ... whatever makes you feel better.
This person did something very wrong, and they should do some soul searching as to why they did it, not try to blame it on human nature.
It is good that they recognize they did something wrong and are seeking ways to change the action, and I truly hope they do use the advice given and put it into action.
Anger is not a prerequisite to abuse, never has been and never will be.