Homeschooling is illegal or restricted in about half the countries of Europe.

> A German family was recently threatened with deportation for homeschooling their kids.

I assume you mean the case from 2013 in which the asylum status of a German family was challenged? While it's true they seeked asylum in the US to homeschool their children (in 2008 or so), the deportation issue was about the validity of the initial asylum grant, not the homeschooling. It appears they were not deported in the end: https://www.cbsnews.com/news/german-home-school-family-wont-....