When you have about 6 positions and probably 1000 applicants, everyone that hits submit and gets through has the 'minimums'.
Quite simply with those sort of numbers above, thats why they aren't interested in people that are 'close' to a CPL or any other way of not meeting the requirement. Not really possible to interview everyone in this situation who meets the minimum....apply for other in demand jobs like firefighter too and sometimes you just don't make the grade to go further. As to why, one makes it over another ?!?!?!
Remember this cadetship was also advertised for internal staff before going external, they won't take substandard candidates, but there are lot of very qualified and capable people in the ranks within the company too.