Any collectivist action that uses the threat of force (either directly by those wanting to unionize or tangentially through taxation as a means to pay public sector unions) is unethical/immoral.
Collectivist bargaining is also BS. It reduces people to a monotonous set of inputs. Unions also tend to end up making it impossible to fire deadbeats and people who do really bad stuff.
I think I could rant for hours about this, but, it comes down to individuals vs. collectives and I much prefer individuals