Nudists try to attract a new generation.
"If a young person is enlightened enough to go to a [nude] beach or resort,..." [emphasis mine]
You know what? Shut up. People who disagree with you are not "unenlightened". People who prefer to wear clothing when enjoying the outdoors aren't stupid or ignorant or uneducated. When you refer to people who agree with you as "enlightened" you are implying that people who don't are somehow defective, and I'm sick of that kind of crap.
It's not that I have a problem with nudism or naturism. I don't think the human form is sick, wrong, or evil, and if people want to run around in their birthday suits I couldn't care less. I don't even care what they look like. If I don't want to see wrinkles or fat I just won't look. I know what nudist beaches and resorts are about: they are about going outside and enjoying the outdoors without any clothes on. They're not about group sex, promiscuity, or pedophilia; and people who go to such places merely to gawk or take pictures are usually asked to leave if their behavior offends others.
One important factor not mentioned in the article is that single men are usually discouraged from visiting nude resorts. Single men tend to be about becoming non-single--even if only for a night--and the ones which are not about that are about the kids. The point of nudism is non-sexual nudity--and so, out of necessity and sad experience, single men are pretty much persona non grata at such places. And in a society where young people are increasingly encouraged to put off marriage (if they ever marry at all) young couples are becoming increasingly scarce. Since nudist (or "nudist-curious") couples are necessarily a subset of that group, declining nudist rolls are an inevitability.
Owing to the fact that Western Civilization originates in temperate zones, clothing is a way of life. We evolved in equatorial regions and clothing might have been the first thing ever invented that didn't revolve around obtaining food, because it let us live outside of our optimal habitat. That's why we can wear the stuff without even thinking about it: so many of our ancestors wore clothing.
It's not that we have an instinct to wear clothes; we don't. In a perfect environment most people would eventually give up wearing clothes as a needless bother--but although we evolved here, Earth is not a "perfect environment". We get cold and need protection from that. Our sun can give us nasty (however superficial) radiation burns, and we need protection from that, at least until our own natural protection ramps up. We wear clothing to protect us from insects and some plants, too.
In my own fiction I have a subrace of humans who believe that nudity is perfectly acceptable "dress" for any occasion. But their world is a lot warmer than Earth is.
What I take exception to is the idea that people who wear clothing (to swim, hike, whatever) are somehow beknighted and clueless. Nudists who want to expand their rolls ought to bear in in mind that there will always be people who choose different things than they do for good honest reasons, and not out of stupidity, ignorance, or overweening morality.
It smacks of the common current in liberal ("progressive") thought: people who disagree with us are stupid, crazy, and evil. People who agree with us are enlightened, smart, cool, and nice.
Still, maybe there is something to that kind of attitude. There may be something inherently attractive about such wording. Let me try a few examples.
"If a young person is enlightened enough to enjoy Wedding Peach...."
"If a young person is enlightened enough to drive a Fiero...."
"If a young person is enlightened enough to own a handgun...."
"If a young person is enlightened enough to be a Christian...."
"If a young person is enlightened enough to vote Republican...."
Hey, I kind of like the sound of that, even if it is arrogant and elitist. It makes me feel as if my interests are perfect. (The fact that these phrases would piss off people who disagree with them is merely a fringe benefit. Especially the latter three.)