c) that a fifth of the 80 million people currently living here have non-german ancestors, and d) as I have pointed out, Germany only became a centre of immigration AFTER WW2.
Yeah, but most of those immigrants are Europeans and I don't think they are particularly responsible for any crime waves. You would be the one to enlighten me if they are.
Europe is not the American continent. It is way, way, way more fragmentized. Poland, for example, is absolutely not Holland, and there are many issues (Which may or may not have been percieved issues and exxegerated) with immigrants from, for example, Poland.
The main problem with people emigrating to holland, for example, is that they usually plan to go there, make a lot of money to finish their study, and go back and finish their study. Or something like that. So they do not bother learning the language (and the goverment does not bother trying to teach them). And then, the immigrants decide that Holland is actually a very nice place to live in (can't blame them for that, since it is, although Belgium is better

), and decide to stay here. Along with a lot of other polish friends. This has happened before with a lot of other immigrants. All of them from the same continent, or from northern africa. For some reason, the people from former colonies of NL actually have integrated better...
Oh, there's something: Failing goverment policy might also be a reason for (percieved) higher crime rates.
For more on the fragmentization of Europe being much bigger then say, the fragmentation in the USA, and why you should never say anything that comes close to 'europeans are all alike and get along very well, you simply need to:
Compare the Dutch with the Flemish (Dutch-speaking belgians)
Compare the British with the Irish, the Scots, or the Welsh, or the Americans
Compare the French and the Germans.
And lastly
Compare the dutch speaking Belgians with the french speaking Belgians. Same country, two completely differnet people's, and the parliament there is a complete cluster****. If you ever though that the US politics were bad because its bassically two parties bickering over each other whilst they want the same thing, due to percieved ideological differences, this is worse: A lot of parties bickering over each other due to a language difference.