I am not going to get into my opinions on parenting. I don't think it matters what kind of parenting you choose, you have no right to judge anyone elses. I understand that this is a gentle parenting forum, but I don't think that gives anyone here the right to judge anyone elses parenting methods or beliefs. If you don't like the way someone else parents, it is not your place to judge, or 'educate', or make assumptions about that person and their children. There is no 'right' way to parent, and to assume that yor way is the only good way to do it and everyone elses are not is sheer arrogance.
People do things everyday that you don't agree with. It isn't your choice and it isn't your role to tell them otherwise. It is their decision (even if you do disagree) and you need to leave them to these choices and stop judging. It is not your place to judge. And I don't think it is your place to 'educate' them, unless they ask you to.
Like you said; they love their kids. They are probably fabulous parents, they just do some things differently. You don't have to agree with them.
The problem with fb is that you only know what they are putting up there. You don't know what is actually happening 24/7 in their houses or their lives. you only see a snapshot status uptdate.
Those who see my fb status updates my think I am a deliriously happy individual who has revolting monsters for kids: couldn't be further from the truth - but my status' do seem to alternate between how happy and excited I am, and how I would happily sell my monster children on ebay.
Anyway the point I am trying to make is that next time you feel yourself judging your friends based on something they put on fb, maybe stop and think "Is it really likely to be as bad as I am imagining it?" "Do my friends love their kids, and would they ever do anything to hurt them?"
If you cann't do that, maybe you would be best hiding their status updates or deleating them as friends - for their sake as much as yours; it isn't nice when you are being judged by someone you thought was a friend.