I believe it's pretty selfish. Times change and cultural norms cause formal lifestyles to become obsolete. If you think the parent is doing something wrong. Then just point it out but don't try to change them. Instead, offer suggestions and leave it at that. Yet, like I said before, it would be selfish if the parent refuses to listen to anyone than her own voice.
To each there own, you can't force someone to educate there child the way you would like. Like saying don't tell me how to handle my children, parents think they know what's best for there kids so people are gonna do what they are gonna do
I do think people should stay out of other family's business (how adults teach and educate their children) unless someone had good reason to believe the child is being abused.