Consider the code version of what you linked above. Imagine submitting a patch in the form of an HTML post on a private website (wrong format), in poor and non-idiomatic style (both for the project and the language itself), full of typos and grammatical errors (bugs?), with the author themselves professing that it's "nowhere near finished".
If someone submitted a patch to any serious open-source project in this form, they'd tell you in one way or another to come back when your patch was finished and was written in accordance with the standards of the project. You haven't done most of the hard part at all: you're complaining about their lack of gratitude for the beautiful lamb dinner you've cooked for them, but really all you've done is dump a lamb on their doorstep and expected them to shepherd it, slaughter it, and prepare it.
(there's a flip-side to this: while the original comment you're replying to is right that (properly) contributing to the official documentation is the best way to support it and better than writing up a blog post, it also presumes that we all have the time or energy for that kind of commitment, which is much greater than that for just writing up a blog post.)