PureChaos said:
Nudity and sex are not the same thing. The reason kids get so curious about it is because all of the grown-ups clamor to hide everything and hush up as soon as they get too close. If you don't treat it as anything special, they aren't going to get interested enough to investigate. Then whenever they're old enough, they'll figure it out as they go.
Kids see themselves naked every day, how is that any different from other people? Kids at around age seven or eight hardly pay attention to that stuff, as you saw. Sure they might point it out because it's new to them, but if the adults don't make a fuss the kids will become disinterested and go along their merry way.
Now, would I take my kids to a clothing optional beach? Probably not. But that's only because I don't like to be hanging around a bunch of naked people at the beach. As for movies with nudity? Those movies usually come with language, violent imagery, or sexual situations that I wouldn't want my kids to see. But nudity on its own is not the worst thing in the world. Every kid goes through some sort of "streaking" phase, where they like to take their clothes off no matter where they are. But then they get a bit older and come to accept clothes as the social norm (at least in those situations) and they forget they ever did that stuff.
Also, how could you not be used to seeing naked people in the changing room by now? It's the
changing room. That's what it's for. Sure, it may seen as odd for someone to do it out in the open when there are other places to go, but you should be perfectly capable of looking the other way. Most places come with family changing rooms now, so if you're so worried about the kids then just take them there. Otherwise, just don't make a big deal out of it. Kids know what to pay attention to according to what adults pay attention to. If you make a big fuss about covering their eyes or telling them not to look, they will do their absolute best to sneak a peek at what you're hiding from them.