Nor did he said that the current Germans are essentially Austrians. Nor.
My interpretation of this sentence is that Germans represent German-speaking European countries (eg. needle gun and Berlin for Prussia, war wagons and Wallenstein for Austria, settler wagons in Bavaria), with HRE as a base. The Austrians are included in this, so the requirement for the Austrians is weird.
Btw, in the past, players used to think of the current German civilization as Prussians, so they wanted to have Austrians. You are now narrating in reverse. This does not make the same civilization become Austrians and then change to want Prussians just because of this sentence.
Anyway let’s see what are the developers willing to give the few remaining slots to. The Danes, Brazilians, Muisca, Mapuches, Congolese, Persians, Omanis, Siamese, or the second German civilization.