Significant part of these territories also had strong historical-demographic links to Poland all that time.
All those mixed ethnicity German-speaking families in Upper Silesia, sure (not that they were treated particularly well in the new state, but then the Communist regime in Poland was addicted to crass racism against its remaining minorities, as you know), but that's a
difficult argument to make for Breslau and so on. But those were extreme and dreadful times in which a lot of people did awful things to each other. Lots of new families in the new Wrocław were
themselves victims of ethnic cleansing of course, and there's no harm at all in finding it very sad that the 20th century produced places like that; ethnically cleansed cities populated in part by families who were ethnically cleansed from elsewhere.