One thing about both programming and music is that they both offer alternatives to the mainstream academic learning environment. Learning either of them can be self paced, and there are options for doing it through teachers, the Internet, in groups, or just alone with a guitar and a record player.

And it's fairly easy to assess your own progress, at least up to a point, and take your rewards as they come. You can also begin doing these "for real" whenever you want.

So it doesn't shock me if a person who seeks out programming for some of those reasons, also seeks out music.