I think this is a lesson in futile effort to control people, and the inevitable repercussions of when those people break free. The parents in this family (apparently) had wild ways in their past, and as a result decided to raise their kids in complete isolation. They are homeschooled, only friends are their siblings, restricted in diet, no learning about the "outside" world, vilification of anyone or anything that is not in their ideology, etc. The kids have grown-up with extreme trauma, resentment and anger. To top it off, the kids are also not at all prepared to deal with the real world - both on an emotional/social level, as well as vital skill level in things the average person takes for granted (eg something as simple as searching for something on internet), as well as needing to get their GEDs, etc. The parents either can't see how completely myopic and selfish their judgments and views are for their children, or don't care. If every single one of your children, by the time they are 'coming of age', want nothing to do with you, perhaps you are doing something wrong.
The positives of this show, is it shows the resilience of the human spirit, and what a gift it is to find and express your true self - and what a gift it is to be able to do that. I'm glad this show has given the older kids the means to build their own lives.