That isn't an "interpretation of the rule of law", that's a response to the bold statement that "We really need to teach [...] all those companies some manners and respect for our society".
Yes, we can introduce all sorts of stupid laws to make foreign companies do as we please or have them leave. No, we're not "teaching" them "manners and respect" for our society. We killed millions of people, not even a hundred years ago, but now we're the paragons of virtue? Give me a fucking break...
>> Because they do operate in Germany?
Clearly whatever they did was legal in however way they operate "in Germany", or there would have been a German court case.