[Modernman]

Once your ceiling becomes the sky, you're not in your living room anymore.

Following your logic, if someone sunbathes nude in their back yard (and nobody other than consenting people see them) they are in public.

Once you put your nakedness on display to others under the sky in public, you're no longer in private.

Why does being under the sky make something public?

[The Brush]

Following your logic, if children (11-17) are naked in their backyard with other naked children present, it is acceptable. and... if parents agree it is acceptable behavior, then it is.
Naked sunbathing to me seems odd in itself. What possible benefits come from naked sunbathing other than no tan lines?And why should children (11-17) be concerned about tan lines?
What's still hanging out here unanswered is, why do you suppose God clothed his (married) creation?

[Oztrich Boy]

Why does being under the sky make something public?

Because then God can see it