I was president of a faculty union at a STEM college that also had a business program. With the exception of the arts and sciences faculty, most of us are fairly conservative.
We have had some issues with union but not many. A couple of the business faculty have pointed out serious errors that management has made in determining the cost raises and so forth. They have in some cased overstated wages and benefit costs by 40%. Pretty sloppy work on their part.
I was the VP of a technical/engineers union chapter affiliated with AFL/CIO. I went along with some co-workers in founding a guild to represent fellow engineers, got enough people to vote for us to represent employees, and within a few years we affiliated with AFL/CIO as a chapter. By that time I was voted in as VP, later temporarily filling in for president when he took ill and left, and I later pushed for an election because I didn’t want to be president. In the beginning, it was very good at representing the employee’s needs and having demands worked out with management. But later on I saw corruption rearing it’s ugly head. Some people involved were more interested in furthering their careers and fattening their paychecks by colluding with management. Reports were created that overstated discrepancies in pay, as you also said, and management went along with it where it benefitted them. I feel I did some good there before I retired, in trying to keep things real. The union was not all bad, not all good, for the employees, as with many things.