Virtually all mature operating systems and many enterprise grade products use the concept of a "super user" that has complete control of the system. Traditionally "root" for UNIX and Linux and sort of "Administrator or Local System User" for Windows although Microsoft never seem able to make their mind up just who is the ultimate authority in their world.
Because of the need for delegated authority and/or separation of duties in larger organisations, we are certainly seeing both the availability and increased adoption of role based administration whereby the actual "super user" account is often not used directly anymore. Instead accounts with powers delegated to them by the super user are the login accounts for real people to control systems.
Clearly there are other ways of doing things but the above model has proven both sound and manageable so why change it without compelling reason?
That being said, jForum's "Admin" user could and in my opinion should be its super user. And for most people that should be the end of the matter - Admin should have all privileges and see everything as a matter of course. KISS principle and all that.
For those individuals / organisatiopns wanting something more sophisticated I suspect jForum isn't really the right product anyway. And there's always the
java security manager one could invoke if paranoid.
Me, I just want to get on with building a forum capability for my web sites. A secure capability, yes. NSA proof, no.