The German government is too busy hunting down homeschooling families, taking the children, and putting the parents in jail.
You forgot about Christian ministers who criticize Islam. Lots of jail space for them.
Well you have no idea what could happen if we Germans would allow homeschooling. All Turks would "homeschool" their daughters in Madrasahs. They probably would not be able to read and write but at least they could recite the so called "Koran" then. Now those girls have the chance on free western education and information provided by the German states. This sparked a emancipation wave among Turkish women that has massive influence on their society in Germany and as an European export in Turkey.
This success is far more important to Germans who are in decisive positions than the "rights" of a few Christian fundamentalists (who are usually deeply influenced by evangelical groups from the US) who want to install a "homeschool"-system in our country. Those people are in numeral and religious aspects a completely irrelevant minority. A few hundred barraters in a nation of 82.000.000. Fact is that homeschooling was never allowed in Germany. The common duty to visit a accredited private or public school is quite old and no spechial heritage of the nazis as some dumb propaganda from America is sometimes alleging. It started with Martin Luther who called for obligatory public schools in 1524. The first relating laws were verbalized in the "Principia regulativa" of king Friedrich Wilhelm I., (1717), and confirmed through the "Generallandschulreglement" of Frederic the Great in 1763. The nazis simply adopted old right in their "Reichsschulpflichtgesetz". They never invented it. After the war the relating laws were pursued and expanded on residents in Germany with a non-German citizenship (US - soldiers in Germany are not affected because of the Status of Forces Agreement).
The "Schulpflicht", the duty to attend a accredited private or public school, is part of our way of live. Therefore it is not negotiable. Neither for Christian nor for Islamist fundamentalists. If someone is living in Germany he has to subordinate himself in a certain extend to our manners and culture. If someone does not want to do this he has the freedom to stay away.
Regards from Germany.
A.B.