Naturism is not equal to sex.
Lots of people mistake naturism and nudism with a constant orgy. Those aren’t the people who know much about naturism and/or nudism. For this, many naturists state that their lifestyle has nothing to do with sex, which is correct. Being naked doesn’t mean you have sex all the time, just like wearing running shoes doesn’t mean you’re constantly running.
Naturists do have sex.
This may sound contradictory to the previous paragraph but it is the only easy way to create new naturists. Naked people aren’t sterile; they don’t use 3D-printers to create babies. They’re also human and, like all humans, they love touching and intimacy.
What better way is there to display that than by having sex with someone you appreciate?
In private.
That’s where naturists have sex. Just like most people they engage in their intimate activities without bothering others with them. If you run into people who are doing the wild thing where everyone can see them, you ran into exhibitionists or crazy people.
Modern ‘awareness’.
I understand that many people have problems keeping all these differences apart. This world is about fast, extreme, superficial. Not about subtleties that require a lot of thought – the powers that be don’t want us to do this thinking. Still it would be a good thing for the folks who keep messing up naturism and sex as being the same. There is a difference.