Look at it critically - whenever you encounter a totalitarian-authoritarian personality bloviating about “those people over there” (others), its usually based on the totalitarian mechanism of ‘avoiding affinity with attributes considered unsavoury’ (filth).
This concept has other applications. If you have two villages, separated perhaps by a near-insurmountable mountain or lake, or if one of those villages raises cows while the other raises goats - this is usually the basis of the formation of a new dialect, accent, or indeed entirely new language. However, when civilization occurs and those two villages merge into a broader community, that language changes to become a unity.
This is observable at an individual level, too. Any unacknowledged or under-recognized similarities/identities/differences between two or more entities will inevitably be used to justify segregation of those entities. The solution, as always, is to identify similarities/identities/differences in a cohesive manner - this is anathema to the totalitarian-authoritarian personality, who is usually pretty stubborn about enforcing, in totality, those under-acknowledged facets.
Of course the reason then subsquently can be inflated, conflated, mixed together strangely, contorted, etc… I’m not doubting that.
The most effective antidote to totalitarian-authoritarianism is a one-way ticket to somewhere distant.
German villages, as comfortable as they are, don’t really promote this antidote.
And how do you know this? What’s the actual argument for why that must the case?
This doesn’t seem relevant to making an argument for the claims in the quoted text.
It couldn’t have arisen just randomly or on a lark.