Re: "Appointed people shouldn't be in the business of making rules. "
"You can't really expect Congress, or any Parliament, to bear the full burden to create each and every specific and detailed rule, often in fields elected people have really no clue about, and rules that may need to change faster than the legislative process allows."
As far as Parliament is concerned it passes legislation that empowers the relevant minister (in practice, of course, the minister's department) to make the rules. The minister is answerable in Parliament, directly and via the relevant Select Committee, and the rules can be challenged in court if the legislated powers have been exceeded. See the discussion above.
To what extent, if any, are the Federal Commissioners answerable to Congress?