Schools usually don't have curriculum that suits child's potentials, learning style and main interests.
There's too much of unnecessary knowledge.
Also, you spare your child of adopting nasty habits of other children. Child can socialize outside of school.
Also, you spare him of bullying and being brainwashed with justifications for violence and all sorts of destructive behavior.
Many tests have shown that homeschooled children are in general more advanced than kids in the classroom. There have been kids who were in special ed in the normal school, who have in fact turned out to be geniuses once they were in the homeschool environment.
In homeschool each child gets the one on one attention that they need, in regular school each child must compete with thirty others for that attention. In home school the kids can move quickly through some areas if they find them easy and spend more time on areas they struggle with. In regular school they must just go to the pace of the regular class, even if it is the wrong pace for them.
I believe home schooling can be a difficult challenge for many adults and it can also leave children with far less social time than they receive in traditional school settings. With that said, I think home schooling can be a better option in today's world. I know in my locale, many children are unsupervised and do as they please and speak as they please. My son is exposed to this activity in social settings with his peers because the parents in my community are too busy working and/or doing drugs to raise their children properly.
Firstly, if a parent doesn't agree with what the schools are teaching their child they are likely to home school their child. Secondly, if a child is having problems with other children at the school, parents can decide to home school their child. Thirdly, if a child is doing really well but is not going up a grade the current grade could be slowing the child down. So, home schooling could be the way to go. If you don't agree to it you don't have to.
Homeschooling is a viable alternative for those students who struggle in a classroom setting or for those who live in areas where schools don't meet parent expectations. Homeschooling is not, however, for everyone. Many students thrive on the daily social contact with peers and the innate discipline of following a daily classroom schedule. Homeschooling requires a lot of self-discipline.