Healthy, well-adjusted kids grow into healthy, well-adjusted adults who will be able to help others. Self-educated kids raised outside the system will grow into self-motivated adults who think outside the system and will come up with new, creative, better ways to help their communities.
I don’t know about private school vs. public school, but it’s already been demonstrated clearly that adults who were homeschooled are more involved in community service than their public school peers: 71% participate in an ongoing community service activity compared to 37% of U.S. adults of similar ages.
Carma (2013). Put Your Own Mask on First: Why Public School for All is Not the Answer. Winging It. Available http://winging-it.me/2013/08/31/put-your-own-mask-on-first-why-public-school-for-all-is-not-the-answer/. Last accessed 20th Sep 2014.