Freedom of sex and nudity

It was a fun night at a country house. Taking another bottle of beer each, my friend and I went out to bring some fresh air to the balcony. Only after a while, we noticed a sweet couple in the pool. They were two pretty girls whom we knew well. But not that much. At first they just splashed in the water and chatted freely. But then, in a fit of everything, they kissed. And again, and again.. My friend was alarmed: "What's going on? We need to stop them before they do something stupid! Is it okay if they have sex here, where anyone can see them?" Me: "Why is it necessary to stop them? And what bad can happen? Listen, I understand what you want to say next. But what is natural human state, if not nudity. What is the purest pleasure besides sex? Enough to decide for people what they should be and what to do. Such taboo sex only causes a bunch of complexes in people. They feel good now. Do not spoil their mood. They want the same thing as everyone else. To have fun, to be happy."