The thing is, too, that for every person for whom "Just write it" doesn't work, there's someone for whom it's permission.
Lots of people come here with the idea that they MUST plot in advance, they MUST have a detailed outline before they start, they MUST know how the story ends first. Not because that's their process, but because they read it somewhere or someone gave them that advice before.
For those people, "Just write it" sets them free. It makes them realize that lots of successful writers (by which I mean writers who have finished a book) start with a character and an idea, not a pages-long detailed outline with bullet points and character factsheets and pictures of models or actors.
There isn't always a way of knowing in advance which people those are.