“Specifically bars” means expressed, not implied; “Act” means the Act, not the ‘charter’.
This is the sort of confusion that arises when a misunderstood issue does the rounds of the rumour mill and comes out as received wisdom that is entirely wrong.
Here’s what really happened.
The obligation to have an AOC used to apply only to the flying or operation of an aircraft for such commercial purposes as were prescribed. The word “commercial” has been deleted from that section of the Act (section 27(9)).
When the word ‘commercial’ was in section 27(9), it did not mean CASA was allowed to ‘make regulations for commercial purposes’. All it meant was that, out of the range of commercial purposes for which an aircraft might be flown or operated, the AOC requirement only applied to whichever subset of those purposes were prescribed. Now that the word has been deleted, it means that the AOC requirement may be applied to aircraft being flown or operated for any purpose, commercial or otherwise.
Note that deleting the word in fact broadened the potential scope of the AOC requirement, rather than limiting CASA in any way.