-My hypothesis is that at least one moderator is a rebbetzin or like a rebbetzin. At least one gives amazing advice and it’s a shame that she must hold her tongue in the CR.
-Another is an aba whose children are grown.
-Another has a smicha and prefers not to be in front of a huge crowd, so he gives back by moderating.
-Another one started the job and then brought his/her friend in to work when a spot opened up.
Those are my guesses.