My take on this, as someone not raised in the US, but living in the US (and being a citizen) for 3 decades now, and having raised 2 kids in the US, that American society respects individualism and individual freedoms, above other values. Thus, the freedom of the parents to raise their kids as they see fit, barring some very obvious and blatant abuse or neglect, is more important than anything else. In other cultures where I was raised or lived, there is more emphasis on the well-being of the social group as a whole, more emphasis in protecting the weak, and less "worship" of individual freedom. Thus, people are more inclined to criticize someone's parenting style if they think that the child is being shortchanged or not getting the best possible childhood, even if the parental potential or perceived errors are not causing major or obvious damage to the child. There is more of a "it takes a village to raise a child", more respect for the values and input of the community.

Both views of life have their pros and cons.