Earlier quoted context omitted.
The standard OP is describing doesn't exist. So whether it "fails to achieve most of the social goals" is yet to be determined. Blocking unrated content seems like a pretty desirable feature to me. Why wouldn't that be one of the "social goals"?
You can turn on filtering and subscribe to a whitelist today. People don't seem to be satisfied with that solution. Why not? The answer to that question is what needs to be solved.
With a universal labeling standard the UX would be much better, and there'd be a much greater incentive for website owners to participate (they'd be implementing a universal standard, not adding support for one particular parental control tool).