Curious about categories for writing

I'm wondering why the writing categories are classified the way they are. Most of the main writing ones are under "personal development." I did find one called "writing" but I think it was paired with English under Humanities. There were some under Business, which I get. 

Why "personal development?" It strikes me as more hobby than whatever. :) I was working on a sort of "who is" page and I'm a writer but I don't consider it as personal development. I dunno, just struck me as odd.