Beyond the core books he said there is support for just about any style of game from some 3pp. So he believes 5e at least has support for lots of play styles.
But this is precisely the unassailable claim I noted previously (perhaps in a different thread). On the one hand, if the system doesn't tell you what it was designed for, then whatever you do with it is necessarily what it is for, and thus the system supports all possible uses; or if you find something you can't do that with, well, you just apply a sufficiently large amount of elbow grease (or find someone else to do it for you) and thus the system supports it.
"Someone could write 3PP for it, therefore the system supports it" is a pretty clear surrendering of the key claim. If it
needs 3PP to support something, at the very least the game isn't actually supporting that thing by itself. Politics is pretty clearly in that direction.
The issue is though this is a very contentious topic in RPGs. For a lot of people, social combat doesn't support social interaction, it interferes with it (because I think for many gamers, freeform RP is the optimal way to manage social interaction).
That said most forms of D&D have some amount of social rules, even if it is just stuff like CHR and reaction adjustment.
And to me, I think this is you projecting your own preference for freedform RP onto a set of players you don't actually know much about. We would need actual data to know this. And guess what, the vast majority of players have never even
tried "social combat" type rules, so they cannot meaningfully answer the question in the first place! "Do you prefer curry over hamburgers?" is a worthless survey question if most people you ask have
never eaten curry. They cannot make a comparison.
And there are many ways to do "social combat." Consider, for example, the extremely popular "Mafia" or "Werewolf" games, which rose to a frenzy of popularity with Among Us. Secret Hitler, for example, has actual mechanics for how the players interact. Or the actually quite challenging Coup, a game of influence, lies, money, and assassination. Its specific techniques may or may not be applicable to D&D itself, but it shows that "social combat" can look radically different from what stuff D&D generally offers, and can be both actually quite challenging
and more involved than "I make up stuff and the DM vetoes anything they don't like."
It's also difficult to design a political system without making political value judgments.
Not at all. Coup has no concept of parties or political philosophy in it, it is meant to represent Italian Renaissance noble families ruthlessly crushing one another. It is a
very political game that makes no political statements at all.
A set of rules for engaging with political situations need not make any political claims. If it provides well-structured resolution systems and tools for interesting tactical or strategic interaction, it has done all it need do.
Your claim is equivalent to saying that you can't have a game like Civilization without explicitly supporting every horrible deed every past or present civilization has ever committed. That you can't have a grand strategy game like Crusader Kings III without openly supporting monarchism or anti-Semitism (since medieval Europe was ruled by monarchs and virulently anti-Semitic.)
Presenting a rules structure where interesting political conflicts can play out is not at all the same as supporting any specific goal, intent, or philosophy a faction within those conflicts might espouse.