I have wondered that myself. "Am I just doing this because I'm a control freak?"
Well, really, I guess so! I mean, you don't allow your 5 year old to watch rated R movies, so what is that? Control.
You don't want your children tossing around profanities, so you discipline them when they put one out there. It's control, too.
So homeschooling is control, but not a "hold them under your thumb control" but a control that actually has more freedom than public school. And I LOVE THAT!