Morale is a function of combat. You’re conflating that with the loyalty ratings of henchmen. They’re different things.
Henchmen could just plain have poor morale and the PC would need to handle that(social game).
Morale is not henchman loyalty. And neither is a “social interaction” system as we’d recognize it today. Loyalty is only for your hirelings, not anyone else. Morale is something you check during combat.
The list when checks happen is on page 36 of the DMG and includes things like testifying and being offered a bribe(social game). The DM could use it whenever he wished.
Which only applies to your hirelings. Not much of a social game. Unless of course you decide to change how it works and why.
Morale and loyalty aren’t the same thing and they have very narrow, and separate, uses. It’s not a “social interaction” system.
Nor is your misstatement of my argument. Stop it. If you can't counter my argument, say so and let's move on. Don't twist it, though. That's just uncool.
It’s uncool to...dissemble...about what’s in the books.
AD&D DMG, p37. The loyalty section is titled “Loyalty of Henchmen & Hirelings, Obedience and Morale”. “The loyalty of all non-player characters associated with a given player character depends upon many factors. First and foremost is the charisma of the PC, of course. This initial loyalty is modified by subsequent factors and the continuing relations between liege and his or her henchmen and hirelings.”
All of those modifiers apply, shockingly, only to your henchmen and hirelings. There’s nothing about using that system for other NPCs. Unless you’re going to try to shoehorn all other NPCs into the amorphous category of “associated”. Which would be laughable as it would immediately produce a world filled with NPCs who “will attempt to kill, capture, harm, or desert at first possible opportunity.”
AD&D DMG, p67. “Morale checks are used to determine the amount of will to fight in non-leader NPCs, and can be applied both to henchmen and hirelings of character types and groups of intelligent opponent monsters (see also Loyalty of Henchmen & Hirelings, Obedience and Morale). Base unmodified morale score is 50%.”
The associated lists of when to check morale and how to modify those checks are, shockingly, all about combat. Like I said.
So yes, if you ignore what’s in the books and/or twist them or repurpose them to support broader social interactions, you’re free do to so. Of course. But it’s a bit gauche to claim it’s actually written that way in the book.
So again, if you ran great social interactions using AD&D, that’s awesome. Good for you. Honestly. But you did so because you’re a good DM. Not because the game supported you in any meaningful way in that regard. Since I’ve now literally had to quote the book at you to prove my point, it would be grand if you’d stop.