All forums have moderators, it is just that some forums are handled by the senior moderators.

In general the busier forums (more active members, and more posts) have more moderators appointed than the quieter forums. If AAdvantage forum, for example, had just 1 moderator, they'd be lucky to last a week - all they would be doing is moderation activity and not getting any benefit from reading & participating in FT for themselves as members.