This teaching may be necessary today, but oddly enough I don't recall my parents ever teaching it to me.
Taken for granted and never crossed my mind. Any more than they'd have felt they needed to teach me not to beat up young children.
I had sisters. I was taught to respect women. I have only a daughter, but I taught her to demand respect.
Ah, but they did teach it to you. Respect for other people was trickle-irrigated into you without your even being aware of it.
We grew up in an America that had a taboo structure. That taboo structure varied from reagion to region, but it acted as unspoken agreement of what would be tolerated and not tolerated. Of course such a taboo structure is a prime target for the progressives who use tolerance and political correctness to cow a culture, so they must corrode and destroy the taboo structure in order to insert their twisted godless ‘correctness’.