Wow, I'm honestly a little shocked - I didn't know that people thought it was wrong to be nude. Especially in art! We're born naked, there's nothing inherently wrong with being naked. Even right now, you're naked underneath your clothes. Your body doesn't stop existing just because you're covering it up.
I currently work as an art model for the classes at my university. I pose exclusively nude. So you can probably guess where I stand on this issue. I really love my job. It's so.. it's just awesome watching people learn and slowly get better as the classes go by. It's really cool to see so many different takes on how you look, too. And I will admit, the idea that dozens of art students are drawing my awesome body is kind of cool. I think it's perfectly natural that nude art is such a thing - the human form has a lot of meaning to everybody (being that we all, you know, have one of those). It's just... it's just something we have contact with everyday, why wouldn't some people draw it?