having 2 major union in the same work environment makes you able to work them against each other (the first one to sign usually gets the better deal to put pressure on the remaining party, you get to claim they're unreasonable in their demands)

blue collar unions are a lot more effective than white collar union : less dissent , the workers are willing to stick together and don't assume they could do a better job than the union rep

it's also a lot easier to compare to similar fields (example a plumber working for the city compared to one working for himself or a major private company) who usually get better pay but less benefits

white collar union often have jobs that look similar and yet have much lower paygrades (just compare the paygrade between La Presse and Le Devoir or Le journal de Montréal)

And they're willing to negotiate on their own since they usually assume they're as smart if not smarter than their reps which seriously undermines the union

If I was a betting man my money would be on the FTQ getting a much better deal than the CSN