Unions are a normal thing to happen to guarantee a check of balances, we are used to systems they have their feedback loop, if you have a one sided relationship you cannot have balance because one side will always try to push in their direction.

The tug between management and unions is the balance.

If you consider that safety is something that is impeding, you have never truly worked at scale nor considered what happens when accident happens, safety is to ensure continuous, painless operation, not impede it and is a baseline condition for trust which is essential to move fast.