I think the question that really needs to be answered is how you plan on enforcing cultural normality. If, as you say, Germans have had a strong identify regardless of historical causes and conditions, it sounds like they’ve figured their culture out throughout the decades and centuries without someone pointing a gun at them over it. So then why should the force and violence of the government be necessary now, and to what extent? Are we just talking arresting brown people, or should we start arresting anyone who speaks something besides German in public, since they’re eroding the culture too?
I also wanted to respond to your remark about emulating the US. You don’t give rich old white men enough credit, they’ve managed to turn the country into a shambling wreck all while keeping everyone else locked out of governance. Maybe if we’d had those other voices, we wouldn’t have Donald Trump soliciting a billion dollar bribe to roll back all of our environmental protections.