Just unionizing isn't always the magic bullet people make it out to be.
Some unions are just downright rotten; only interested in taking the dues and doing jack shit for the workers. There are quite a few Hollywood trade unions in my line of work that are corrupt to the core, don't know much about or care about the core skills they claim to represent and do nothing but leach off the workers and bleed the studios. The joke of 'negotiation' with bad unions is them basically working to enrich THEMSELVES and screw the workers- and many times screw the core business as well. Many would rather cave and take a payoff than go to bat for any worker grievances if they can help it. Keep the busses rolling; need a steady supply of them to toss workers under!
On the other hand, there are awesome unions that really understand and fairly represent the skillsets involved, really do work to protect the employees, push for higher wages, and use their muscle to go to bat for the workers when needed. (Like my union, the Screen Editors Guild- they are a powerhouse and are awesome to belong to. Employers fear crossing them, treat their members right, and respect them at the same time.)
So unless you know the situation (and honestly, the UAW comes off as the POSTERCHILD of the first mentioned type of union, not the 2nd) then maybe learn the actual situation on the ground or STFU about preaching to others about what their best interests are.