Were you in government or private sector?
Do you know the massive difference between a government union and a private sector union?
I was in government, federal agency. What I know from over three decades of management is that there are abuses on both sides, management and employees.
I knew of managers who violated contracts on a regular basis. I also fired union employees who violated those agreements.
I was told more than once by the highest levels of management to do things that I knew violated our contracts and I always told them that I would follow a direct order if they put it into writing. They always backed down when I told them that.
Once the employees knew I would stand up for the contract, I had very few problems supervising union employees. If I had been a craft employee, seeing the abuses and willful violations by some managers, I would have joined a union, too.