Unions are not just for getting higher wages. They're not even just for when conditions start to get worse. Unions should be there for the best as well as the worst working conditions. Unions serve to maintain good and improve bad conditions, it's not about going against the "boss", it's about actively or passively defending the workers' conditions.
Would you trust your boss' lawyer saying "the trial will be fair, you won't need a lawyer"?
Business are soulless evils