The Muslims in Europe are the guests of the local people, and should learn to behave as such.
Sven Lau, the initiator of this Sharia Police, is not a "guest" by any definition you probably mean though. So, I'm not sure what he was supposed to learn.
For some reason, an astonishingly high number of prominent German Islamists don't seem to possess any "ethnic" background. Sven Lau, Pierre Vogel, Bernhard Falk, two of the members of the Sauerland terrorist group... I guess Denis Cuspert technically qualifies as well, since he's only half-Ghanaian, never knew his biological father, and didn't convert to Islam until he was 35.
So what's up with German convertites? Is it because of WWII and the Holocaust that Nazism is considered not politically correct enough even when you seek to become a homicidal madmen and instead becoming a Salafist is the way to go these days? 
If you can trust Speer Hitler did phantazise about a Germanic Islam taken over by the Aryans after Islam had defeated Christianity with its worship of weakness. Islam with its emphazis on strenght and martyrdom was his prefered version of monotheism.
