There's shitloads of secret communities everywhere. Discord is particularly popular. The reason they exist is that average people are only averagely intelligent and averagely interested in most topics, so if you want a higher level of content than average, you have to go where they can't find you.

When a dance club is cool, nobody knows about it. When everyone finds out about it, those cool people go somewhere else. Being cool, itself, implies being something different enough from normal to necessitate its own word to differentiate it. Think hipster.

Average people made McDonalds the worlds most successful restaurant. Not everybody wants to live on big macs though. But on the internet, where the users control the content, they find your cool burger place and accidentally turn it into a McDonalds because they don't know the difference.

In my experience, most people outgrow the secret clubs phase eventually. But I'm sure not everyone does. Who doesn't like feeling special, no matter how unjustified it is?