Since it was my edit that prompted this, let me explain why I kept the Jazz tag in.
Tags are used to filter questions into smaller segments, so that experts or knowledgeable people of a particular tag might find those questions easier. These people are the target market of that tag. That's why tags exist; they are keywords just like you might use in a google search.
By putting the Jazz tag on a Jazz musician, you're inviting Jazz experts to look at your question. And Jazz experts are the guys who are going to know about the more obscure musicians in Jazz.
To me, every question about music or musicians should contain a genre (rock, blues, jazz, etc...) tag. It just makes sense to capture as much of the question's audience as possible with one small word. Questions about song's meanings do not, because the genre is inconsequential.