Anyone who admits to punching down wants to be powerful and cruel

No one admits to punching down. It's made up so people can be viewed as less powerful than they are, or so the speaker can appear to protect them. "Punching down" always means "I haven't been given the social right to call you out on your shitty behavior, so instead I'll pretend you're vulnerable to get sympathy from others and permission to call you out". If you're not regularly getting excluded from social circles for speaking your mind, you are not punching down.