"Please do not get me wrong. I am 100% for your right to do what you will with your children, only that I question how well you can provide all the time."
The problem is that the average teacher isn't much better than a "well-meaning amatuer" parent. So much of classroom time isn't relevant to learning any specific subject. Teacher opinion, discipline, silly social engineering games. Public school test scores are a testimony to how little learning actually takes place. Even a sloppy attempt by a parent following a homeschool curriculum manual will do better in most circumstances.
I have many family members who work in the public school system ranging from principal to 40 year teacher. They all support and encourage my homeschooling efforts. You wouldn't believe the stories I hear from my brother who is a principal of an elementary school in California... about the teachers! That being said, I don't mean to offend the precious few outstanding teachers out there. We know you're there and that you do good work.. but it won't repair 4 years of sloppy teaching by the others.