That's what I find strange with the often-seen "well, just vote with your wallet" argument when a company screws up; it's almost literally the definition of an oligarchy (IE, more money = more decision power).
However, when Unions show up, they are the equal and opposing force that keeps a company in check with regards to their employees. Some have issues with Unions, as some of them are significantly corrupt. But by and large, unions are the equal and opposite force.
What protects small companies from large companies? In reality, nothing. That's what allows fake-patent shakedowns like the "SSL Patent", or others. And that's by exploiting protections in law... But what happens when one side has *10000 the resources? You capitulate and go bankrupt due to legal fees, legal harassment, and a continual defense against a legal monied attack.
In the end, there's fuck-all you can do. Well, other than whatever the monied plantiff wants.
Yeah, free market. Like "I have more money, and I dont like your face, so I nuisance sue you until you're bankrupt." free market?
That's not a world I want to be part of, continue, or assist in any way.
What kind of world would it be if we didn't even have rules about things like how much lead is acceptable for a person to consume, or what constitutes 'acutely toxic,' or what you are and aren't allowed to put in food?
"Well," the free market idealist replies, "it would be fine. Nobody would consume things with a lot of lead over a competitor without lead. Nobody would use unlabeled toxic things after the first few incidents. Nobody would eat or drink poison over a nutritious competitor."
And that malicious failure to acknowledge that people are not omniscient or in possession of perfect information about The Market on a second-to-second basis is what leads to us accepting those sorts of stupid arguments.