Hi Kyle,
Having a weird problem. The moderators are set to be "Main admin site" and they can also edit users but ONLY if the users are also in the PUBLIC user group. If they are not in the public user group, I cannot edit them.
Please see the picture below. As you can see, a user has only "Main Admin Site" (the moderator) and I can only edit the two users who are in the public group. I cannot edit the others.