Yomama, if you read your quote carefully it say that "Überwiegend" that most dual citizens come from "bi-nationale Ehen". So IF you are born a child of a German and a Turk Citizen you can be a dual national.
There are alsao a VERY FEW "hardship cases" and loopholes where it is tolerated.
When I got written to by Munich City Council with an offer of citizenship, the letter said very clearly I'd have to give up my British Passport. Until I saw this thread and then the link, I has NO IDEA that the laws had changed for certain EU Citizens and that would be a story I'd be following very closely!
And I think people SHOULD be given full citizenship and voting rights after 12 MONTHS! To borrow a phrase from the USA (just to prove I'm not "anti-American":
NO TAXATION WITHOUT REPRESENTATION !