I don't think it is some secret. There are many who say that art is not just a painting itself, but in the process of making it, and the motivation and goals behind it. Generative "AI" has none of that. It does not labor like a human would. It has no motivation, because it is not a thinking being. It has no intention in making a digital output. It just works. It has no meaning by the process of creating. Some Michelangelo working on something amazing for years, that's something that has meaning.

It is also not inventive. It's rehashing and regurgitating. That point is a bit muddy, because many humans do that too. But ask a generative "AI" to make something better than what it has learned from and new, and you will probably be disappointed.

I am not an art buff, but I can sort of see, why one wouldn't consider it proper art.

> Is true art a hermetic endeavour which must be gate-kept to seal out the lesser folk?

Kind of. If everyone on the planet can paint the Sistine Chapel’s ceiling, then it’s not anything special anymore is it? Especially if it reduces the process to asking the world’s most prolific counterfeit machine to do it for you.

People are aren’t entitled to get entry into every space they want to with no effort!