Kids can get on your last nerve and any parent will tell you that. They know exactly how to try your patience, and what makes dealing with them so frustrating is that literally everything you do for them, including rules that they think are lame, is entirely out of love.
So I get that it's easy to lose your temper with kids. I get that you maybe clean up their toys angrily by throwing them in a toy chest or raising your voice at them after you've told them to not pee on the kitchen floor or clean up after themselves for the millionth time.
But I'd wager that even parents who physically or emotionally abuse their kids from time to time don't feel so good about doing it, and would never even try to argue that their abuse is "justified". The ones that do are pretty scummy, especially when you consider that all psychological studies show just how harmful it is.