I was just responding to that particular point in your post. I don't have any strong views either way on homeschooling.
However, that being said, for math in particular, some of the curricula available to homeschooling parents are truly excellent, especially Beast Academy, JUMP Math, and Singapore Math.
I'll clarify. When I say one needs training to be a teacher I'm talking about statistics. I don't mean literally that no person can be good without training. I mean that statistically speaking it is unlikely that a person with no training in a subject is going to be better or as good as the average teacher of that subject.
However, that being said, for math in particular, some of the curricula available to homeschooling parents are truly excellent, especially Beast Academy, JUMP Math, and Singapore Math.