Willie,
The 30t rule was introduced to exclude -200 drivers some time ago as it was deemed they were having difficultly with transition courses onto the Boeing and Bus. More a case of playing the man and not the ball, just like most rules made over here. So those prevented from joining because of this can thank a group of 200 drivers that joined 3 to 4 years ago.
Not the first time this has happened, as the 55t rule was originally made to prevent 146 and 732 drivers from accelerated commands when they were happening thick and fast. No reason for that either, so see that man vs ball comment again.
The Don