I actually think this early adventure is a great piece of worldbuilding from Matt. It is SO effective.
(Spoilers for the whole campaign)
Think about it: our party has so far encountered one goblin and been explicitly told by a voice of authority that goblins can join civilized society, but that it's rare and only individual goblins have ever done that. Then their next big fight is against gnolls. Gnolls who are carting away dead bodies and kidnapping people. Some of them are undead. They're seen eating raw humanoid flesh. They attempt to eat a child. They only communicate in barks and yips, like dogs or wolves. The scenario is clear: these are monsters. These are unambiguous threats. They must be destroyed. There is no point in attempting to communicate with them. And in this encounter, all of this is true.
This sets the expectation: gnolls are enemies and monsters.
(The following 20 or so episodes provide more examples: the enemies in the fighting pit are wolves, otyughs, trolls, giants, and minotaurs. They are waylaid on the road by a band of goblins who are working with ogres. These are your unquestioned enemies, the scenarios say.)
So when, in 40+ episodes, the party goes to Xhorhas, there is a reason for them to be SURPRISED that bugbears and ogres and goblins and minotaurs and gnolls are living in a city together. There is a reason for them to act like "My whole worldview is being thrown upside-down". Even though the actors have not been subject to a lifetime of Dwendalian propaganda that these are creatures not people, the encounters from early in the campaign put that in their mind instead.
And there are hints that maybe there's more to these "monsters" than at first glance. They are organized, they have set traps, they aren't mindlessly slaughtering. They are eating raw human flesh, but doing it in a ritualistic manner. There is a human who speaks in Common to them. There is something more to these gnolls, and therefore all gnolls, than just being monstrous. But because what they are using their intelligence for is so grisly, those hints of intelligence are missed.
This whole early adventure is such a great example of in-universe world building. I'm sure there are other examples in these episodes I've missed.