Here's a more accessible analogy: Here is Jacques Pepin making an omelet in 2 ways: https://www.youtube.com/watch?v=s10etP1p2bU

You can see every motion, every measure, the size of the flame, there are no cuts.

But if you actually go ahead and try to make this it turns out to be INCREDIBLY difficult to get it right.

Not every random mish mash or scribble is as random as a layperson will at first think.

The other analogy is look at the original post. Picasso COULD have painted like he did at 15 or 18 or 20 - which I assume you would agree you couldn't scribble yourself. But he CHOSE to paint in the style you are criticizing. You should default to assuming that there is more skill to it than you can see.