Yes, I understand that the workers are unhappy with the way their union has negotiated for them, but I don’t see how that’s relevant to the employer not paying the negotiated amount. Why is that a failure of the union like the article states?
As far as I understand it, the decertification effort seems to be about a previous unpopular collective bargaining agreement. The issue that the article highlights is that the union agreed to a workaround that didn't work for everybody. I'm not convinced that enough people would be so inconvenienced by this workaround to move the needle on the (already weak-looking) decertification effort, personally.
A union is more important when you’re working for the Federal government or even some state or local government as they make and enforce the rules.
For example, if you work for a state labor department… Public sector worker safety is regulated by… the state labor department. There’s an organizational bias to not rock the boat.
Any Federal or quasi-federal agency is a dictatorship. Some rural mail carrier in Montana or New York is 50 layers away from someone who has the power to affect change. You need the union to represent your interests and short circuit the org. Outside of the federal space, if a company fucked up payroll, the state labor department would unleash significant pain on the company. USPS is tasked with policing USPS!
If the union is failing some constituents, that’s going to drive a desire to get more effective representation. The benefit of focused representation may outweigh a smaller bargaining unit. (In general, it’s better to have 500,000 members than 50,000 members)