I didn't take offense. If that's your definition, it's no wonder you see it everywhere.
You're definitely misunderstanding. Usually, I find that means the other person doesn't want to understand, but I'll give you the benefit of the doubt.
I didn't necessarily mean physical bullying. I used the "pick on someone your own size" as an example from childhood. You were supposed to extrapolate the idea that it's to not pick on people below you on the physical or social power ranking.
You clearly don't like race as an example, so let's take sexual preference.
Speaking plainly: one of our two political parties and one of our most influential religions - the GOP and white Evangelical Christianity, respectively - are openly and officially anti-gay.
In other words, divisions exist regardless of what you or I do/say/think. We can't wish them away. It's meaningless to say, "Stop trying to divide people, that doesn't look good on your part, nor does that help anyone. It does the opposite."
We are already divided.
My bringing it up has nothing to do with it. You not liking it has nothing to do with it.
We. are. already. divided.
Divisions. exist. regardless. of. what. you. or. I. think.
So dump the division arguments, they're settled. The question is what to do about it. My suggestion is that we define punching down as offensive. People lower down the ladder get kicked around all the time anyway, why add to their problems?