The real issue is the power imbalance with the subcontractors. There used to be a set model. In other words, the wages paid in small airports were comparable, and those paid in the big airports were a bit higher.
Place of work aside, you can appreciate that, in Montreal, the competition for workers is fierce and everyone is fighting for them. I think people would accept lower-paying jobs just so they don't have to work at Montréal-Trudeau International Airport, because getting there is a lot of trouble.
The wages are comparable across the country, but the problem is the attempt to target one place in particular and impose the same working conditions elsewhere. That doesn't make sense because every province has its own economic challenges.