It can be explained easily if you've been around a while. At the top of the list of reasons is the hatred of pilots by the head of flight ops and engineering. The feeling is mutual by those in both those departments.
Inexplicably, he was brought into that new position after the Joburg accident and has hated drivers ever since (and probably before).
He makes rules in order to screw YOU around but which, due to their affect on the system, are often later changed or simply ignored.
If you hate the current "system", his new format for bidding (under development for a year or so with lots of money put into it and reportedly due out soon) is really going to impress you. Nothing new - just new to this airline.