Why is public nudity wrong or immoral? Please explain.
I don't believe it's wrong or immoral. I suppose that our society has constructed certain boundaries of appropriateness that it would be odd to transgress: for example, shopping at the supermarket, or going to a business meeting I think would seem odd if done naked. And I know many faiths, including my own, believe that it is disrespectful to appear in a place of worship nude, which I can understand.
But I can't see any reason why people shouldn't be naked at the beach, or puttering around their yard, or in parks, or working out, or dancing, or other such artistic and recreational activities.
Mostly I think people need to get over the whole nudity taboo. So you see someone else's junk. Whatever. It's just skin. We all have bodies. If God didn't want us to be naked at least some of the time, we'd be covered in fur and our junk would all be inside.