And why are police never punished, because police unions. Unions in their modern form are granted special privileges by the government and use those privileges to extort society. There is nothing wrong with people joining groups, collective bargaining, etc -- the problem is that they are given special privileges by the state.
I don't even understand what you're arguing. Aren't corporations given special privileges by the state? Are you against that well? Can you clarify what you're arguing here?
If any group is being given special privileges by the state, it's the police...
Normally, a union is formed to balance the power of capitalists with the laborers they employ. In the case of law enforcement, there is no capital, nor is their labor being used to produce something of value. If anything, law enforcement defends the interests of capitalists, rather than being subject to abuse by capitalists.
Police unions have no solidarity with workers. They're groups that exist only to protect themselves, and they're happy to suppress strikes when it serves them. It's facile to consider them as part of labour unions.