The United States is a land of immigrants, Germany is not,
and in order to obtain a German citizenship, an applicant has
to be either born in Germany, have German parents, by adoption through German parents, or by naturalization.
The requirements for naturalization are: 8 years of residency,
loyalty to the free democratic German constitution, adequate
command of the German language and no criminal record (among
other things)
Here is a complete information from the German embassy
http://www.german-embassy.org.uk/reform_of_germany_s_citizenshi.html
Germany has had its fair share of problems with Muslims
throughout the years due to cultural differences, and especially wifes and daughters of Muslim men have become
victims of violence due to them adopting to the free democratic lifestyle, Muslim men won't accept.
If one wants to obtain the citizenship of another country, it is understood that the applicant will honor and oblige by the rules of the new country.
This wasn't any different when I applied for the US citizenship.