Public sector unions are inherently problematic.
The argument for a union is that they keep a company in check and the two balance each other at the negotiating table.
Public sector unions negotiate against voters and tax payers. There is really no opposite force to resist against their negotiating power and the only hard line is the state budget.
100% agree with this. Yes government's can also abuse it's workers, but society can more easily vote out an abusive government (especially locally) than an abusive CEO / board. There's no perfect solution, but police unions are a pretty good example of a worst case scenario.
I'm very pro union in the private sector.