Please update the info
(EDIT: I did it myself, looks like everyone can edit artists now)
That's weird. If I'm not wrong, it was decided sometime ago that only Moderators and Editors could edit artist pages. I don't know if this has changed, though.
I have asked the Admins about that. It's not a bug. All users who have 1500+ points are able to edit artist pages. You have (at the time of this comment) 1645 points, so you're able to do that.