We are having a communication failure here.
You wrote, see the emphasis, «[/]superior[/] first world» in apparent reply to member flohofwoe's «former Soviet scientists and engineers trying their luck with 3rd world despots». You wrote that «"third world", according to [some] Western definition, ... were those countries that were poor (and also perceived as primitive and culturally backwards, so the term eventually came to be seen as stigmatizing, at least with left-leaning people)».
When people mention 'third world', they are assumed to mean Sauvy's frame - there is no subsequent one overriding it, it is still the reference. "Third world" means what that short piece you read proposed. Billions of people trying to bend language, concepts and culture have the weight of a hefty nuisance, not that largely opposite one of Authority.
In Sauvy's frame, 'third world' has no connotation of «[infer]iority», «primitiv[ity]» «backward cultur[e]» or «stigmatiz[ation]». And «hunger and misery» are just facts relevant to the phenomenon, of course they are there, they are part of the point (they are grounds for the parallel with the "third state" near the French Revolution) - they are not appreciative nor depreciative, they are analytical.
If people said "third world" as a disparaging label, it is their own fault, and you cannot assume it in instances - you can suppose it frequentistically, but you cannot point to John and take for granted that his speech yesterday meant what the laymen at the bar would have meant.