Those five are "supermoderators," they have moderator status on all forums here on the site. With dozens of forums and over a quarter of a million members, moderating this site is a tremendous undertaking that really does require all of these people.
The counter at the bottom of forum listings just shows how many members are viewing the site, but the moderator list just shows all of the moderators for that forum, it doesn't mean that they are all looking at the same forum at the same time.
HTH