Well you asked. Here's the answer.
If admins are not active on the forums, it is for all intents and purposes impossible for them to know the rules to date, and thus impossible for them to administrate successfully.
That, and in my opinion it's a matter of priorities. If he doesn't check the forums that often, something tells me that he won't really care about the community that much.
In my opinion I'd rather have a handful of dedicated admins rather than 1 dedicated admin, 5 lazy admins, 2 or 3 idgaf admins, and 1 trololol admin.