Your posting is appealing because you're not saying that homeschooling is a perfect thing but may backfire in some cases.
I understand that you put the freedom of the individual on top priotrity and you want to assure that you have as less state as possible.
I know about religious madrasses and I would see a possibility of homeschooling as a weak point in legislation to put children there INSTEAD of sending them to school.
My argumentation might fall flat in america and I honour your experience.
But we are talking about germany - and here teachers are officers that stand under an oath inding them to our constitution.
Every school book is examined by a committe consisting of teachers, representants from churches, family organisations and other groups before it is allowed to be used in schools.
The access to the job of a teacher is only graned if you are able to proove that you are not an extremist.
As an example extreme left wingers that tried to get employed in german schools during the 60s and 70s were excluded from office.
Homeschooling as opposed to the german teaching officer does not stand under control of the public - therefore indoctrination is certainly a lot easier.
You wouldn't want your children to eat something that has not been controlled by an organisation that stands in the bright light of the public - why would anybody want to have them taugth at home ?
Homeschooling is only appropriate in rural areas - or if the offered public education would just not be good enough as a base.
We can exclude both for germany. (Until today)