It’s mostly Arabs which have trouble fitting in due to the vastly different organisation of society, down to predominant family system, while e.g. Turks fit in quite well. Gesticulating mediterranean drama queens, sure, but so is everyone from Spain to Greece. There’s also a fuckton of Turkish-Arab beef. Afghans are also usually completely overwhelmed but also much more cut off from their background and on top of that accustomed to a multi-ethnic society. It’s more of a “start a new life” type of thing for them, less “bring your clan baggage with you”. Iranians don’t even register, Albanians if then as Balkaners.

I guess the reduction to “Muslim” might happen organically with easterners as Turks never really made it there in appreciable numbers. Outside of Berlin, that is, and the rest are pretty much invisible. Like, imagine if the only English-speaking people you ever met were all Americans, what you’d think of English speakers as a whole.