We Need to Have A Talk About Writing...

One other way to look at why I wrote my original definition so broadly.

When we define something, we tend restrict. Who is in the club. Who is left out. Why?

If you are at a party, and you ask somebody what they do, and they say, "I'm a writer!"

Are you really going to challenge them on their credentials or qualifications on that? would you do that to any other response?

Short of finding out that one guy in your writing group is just a poser and has never written anything, there's no need.

If somebody self-identifies as a writer, it implies they write. Whatever their reason is, it's distinctive enough in their life for them to say so. That is likely what it means to write, at a level beyond completing a bit of homework.