The consensus on that list is that License Zero violates certain tenets of the Open Source principles, and as such software released under a License Zero license is not open source software. By extension, this means that getting to work full time on License Zero software means that you’re not working full time on open source software.
> FreeDB avoids this problem by supporting multiple entries for any given disc.
FWIW, something somewhat similar to this will Soon™ be part of MusicBrainz too: https://tickets.metabrainz.org/browse/MBS-4501 – you might want to read through there and maybe even put your own thoughts about what it can be used for in a comment on that ticket.
> MB […] used to have rules specifically banning anything except Camel Cased English Literary Title style
Just out of curiosity: When was this? I’ve been involved with MusicBrainz since summer of 2006 (ie., for over 10 years) and this hasn’t been the case for as long as I’ve been around.