Its probably because some beancounter has decided that it is not in the mid-term benefit of the company to have more new entrant 737 pilots, as they can still keep 30% of the 737 crew moving round the country in taxis at any given time to plug all the holes in the program.
Of course this leaves no standby cover at -300 bases like LPL, LTN and EDI/GLA because they are also covering EMA, STN, BRS and of course each other all at the same time. But what the hell! As long as the pilots believe all the sh!te about the new rostering, watertight crew planning and all the other promises BALPA wrote on the back of a fag packet, then us poor suckers will just keep doing it and drawing our paychecks.
I am sorry that the courses have been cancelled - sorry for you, for me and my colleagues. It is just another example of double standards and hypocrisy in a stupid company.