"If all airlines are just allowed to make people redundant at the drop of a hat everytime they move or remove an airframe then none of us can sleep soundly in our beds at night can we?"
Unfortunately that has been the case in the non-airline world for 150 years - technology changes and the staff take the hit - not many traditional printers, or hand loom weavers around......................
PS I suspect the "re-training" issue is a red herring - they just want/have to cut the numbers of staff fast - retaining people to have to cut them anyway - no chance