Can someone explain why LLM's write like this when most humans don't?

I asked ChatGPT about that and it gave a nicely reasoned explanation on what AI produces compared to humans.

But that being said, the problem I think is that people treat the output from LLMs as final.

It should be treated more as idea generation or early draft to get over the “staring at a blank page” and get the creative juices flowing and creating your own content.

Having purely AI generated content and eventually feeding the algorithms and soon enough every sounds the same (already does in a lot of places).

Most humans don’t, but maybe “most humans” do? As in, on average, as a collective, regressed to the mean of mediocrity and devoid of personality, we write like this? It’s not self-deprecating, it’s humbling.

I suppose it might be because humans that use LLMs write like this.