I recently stumbled across a user profile with the rank "Fred Durst." Despite having zero points, this profile had submitted 39 bands. So I guess my question is, is this a rank that is applied by mods to users who are banned or something? Or was there once a time when you could write in your own rank?

Correct... by admins.

Seems like you've been interested in the site as of late. Answers to most questions of this kind you'll find here:
https://www.metal-archives.com/board/vi ... 2&t=114257