At my former job, my union rep and I did not see eye to eye on many things. We had intelligent discussions and grew to respect each other immensely, even when we clashed in frustration.
Examples of why I don't like unions for nurses:
1. Unions defend rules against pragmatics. Immediately after hurricane Sandy, I was assigned to help open an additional telemetry unit for the influx of patients needing monitoring. The hospital space and staff were stretched to the max. While transporting a patient from the ER to the new unit, the union rep tried to stop me; apparently it was not in my job description to push a bed. "It sets a precedent," she said. "It's about the patient, and It's an emergency situation." I replied, and continued until all 8 patients were transferred.
2. They protect dangerous workers, no matter how they deny/justify. Long term nurses who could no longer safely function in their position kept their places because of the union, even when these nurses were incompetent, physically unable to perform the work, or both. If a nurse has difficulty getting up from a chair, they don't belong in the ICU.
3. Unions have devolved into gangs: mandating who members vote for, bullying, intimidating. In the early 90's, 1199 went on strike in Philadelphia. At the Hospital of the Philadelphia College of Osteopathic Medicine (no longer open), union workers physically assaulted Dr.'s, vandalized lab equipment, and prevented loved ones from seeing their families. Unions forget they have a right to PEACEFULLY assemble. This does not mean blocking streets, denying others access to public places, and committing crimes.
I'll never forget what I saw in Philadelphia and will never support a union again.