It is a little bit short sighted and clear lack of knowledge, which is surprising from a former spinner to group the doorsa and carron ball together. Anyone can bowl the carron ball without flexing.
I always find it strange that when an Australian coach see a good leg spinner, the teach him the wrong on. But when an Australian coach see a off spinner they don't teach a spinner the carron ball. They invented the ball.
If that the thought process from the top of Australian cricket, let the spin cycle continue for many more decades.