There are some people that believe that writing is an act of creative expression. In other words, that writing is primarily about the act (and as such, it's a quite selfish activity). Editing destroys the expressive act and must be avoided.
These people's writing is usually incoherent and they are very proud of it. If you've ever read a bad new-age self-help book you've probably encountered writing like this.
Good writers understand that writing is about communication. The initial act of writing (ie, word puke) is worthless. What matters most is a piece of writing's ability to communicate clearly.
This writing is usually pleasant, concise, and clear.
Actually, unless they are self-published, most "new-age self-help" books are pretty thoughtfully edited. They are persuasive writing, whose goal is to convince you to believe in a framework that is not supported by evidence. Dismissing them for being incoherent is actually a mistake, in that it shows a lack of understanding of their appeal.
Though, I must admit, I'm not sure exactly what you meant by "new-age self-help" books, so I took a guess.
> There are some people that believe that writing is an act of creative expression.
I think "some people" might be underselling it, as evidenced by the borderline innumerable fiction books in existence?
> and as such, it's a quite selfish activity
"quite" seems a bit harsh, surely "writing because you enjoy it" is pretty far down the list of all "selfish" activities? I'd imagine many authors also write because they think others will enjoy their works.
Creativity and concision are not mutually exclusive. Read Ernest Hemingway or Cormac McCarthy. Their books are concise, almost spartan, clear and pleasant to read, and undeniably creative.
This style of writing is deceptively simple, of course, and devilishly difficult to produce.
You may find that there is a continuum between textbooks and poetry; and that some folks want things that are further over towards the prose and poety side, some of us enjoyed reading Kerouac, we don't care about perfection so much as feeling a piece channel the spirit of the person who wrote it. What is being communicated is not always just the raw parsing of the text but something more, a gestalt of what it meant for the author to be writing that particular kind of thing at that time, in their lives and in history.
"Good writers" are... a matter of taste
I 'm sure you consider your opinion to be correct, but there is something to writing being an act of creative expression. It's fine for it to be a selfish activity. Diaries are this way, for example, and the negativity you point at other people's hobbies is unfortunate.
There's something to the idea that if the writer is writing with the intention of publishing it, that should be edited. But if you're writing for yourself, and happen to simply keep your writings somewhere public, some other person's desire for you to edit more is a measurement of that other person's feeling of entitlement.
I have about as much desire to read some publisher's edited version of Anne Frank's diary as you appear to have to read the original.