Regarding your encounter on the nudist camp, I understand the person who came and tell you that you couldn't take pictures in a nudist camp. That's very easy to understand on a let's say "moral" ground.
Although one might wonder if the place was a public one, a private one etc. and could challenge maybe the injunction on juridical ground, one might expect people don't want naked photographs of them freely circulating.
I understand you were not taking pictures of people, but the "warden", or the other persons on the place, might not feel like being on a surveillance duty specifically on you to see where you turn your camera. It certainly is something that make people feel uncomfortable that there is a guy with a camera, regardless of where he's actually pointing it.
Some people doing street photography, you know, do exactly this, point the camera first somewhere else, and then on the intended subject.
* As I like saying: "I'm not anti-feminist. I'm misogynous".