Prof Schwarzschild Calculus:
Dr. J.W. Müller : As German as sauerkraut or brätwurst
Hmmm...
This has been discussed before, and the answer is less clear-cut than you are stating, I think: the jury is pretty much out on that one. We don't even know that his name was actually Müller, let alone that he was German.
Prof Schwarzschild Calculus:
Marshall Kurvi-Tasch
I'm not certain what you have done to come to that conclusion; it obviously plays in some ways on Hitler - but Hitler wasn't German either, he was from Austria. That aside, the setting of Marshall Kurvi-Tasch's regime is Borduria, so one would have to assume (until information for the contrary appears) that he was Bordurian.
Prof Schwarzschild Calculus:
Müsstler in King Ottokar's Sceptre
Again, there is a play on the name of Hi
tler, but equally it's a reference to Benito
Mussolini too, so it's a long shot to say that he's a German, rather than just a pot-shot at European Fascist dictators in general.
However, these points only dispute the details of your argument: broadly speaking, I agree with your proposition, and think that Hergé, along with many Belgians following the occupation of the First World War (and, inevitably the Second too), found it hard to think fondly of the German regime at the time.
In many ways, the clearest exposition of this isn't the later books - if Krolspell is a German, then it is more to do with the fact that Nazi war criminals on the run had become a mainstream trope for thriller writers by the time
Flight 714 came out, than as an indictment of German criminality.
No, to me you have to look no further than
Tintin in the Land of the Soviets, which book devotes almost as much time to lampooning the ways of the Germans Tintin encounters, as it does to exposing the Soviet Union as a corrupt system.