That's not the case. A union is an organization for extracting rents above those the market would ordinarily bear. Rent-seeking activity --- no matter who does it --- makes society as a whole worse off. Bastiat showed that a long time ago.
When corporations organize to extract rents, we call them cartels and apply strict penalties under the law. Why should employees have a right to use these same tactics? The market for thee, but not for me?
The operative word there is "normally", which makes your claim tautalogical. Unions do increase the cost of labor compared to a market without unions, but this is simply relative. You haven't (and I claim that you cannot) provide a reason that the cost of labor without unions is more natural, and isn't simply unnaturally suppressed by an imbalance in market power between job seekers and providers.
I reject the premise of your claim. The market price isn't just one of many prices from which we should choose arbitrarily. The emergent market price is special. It's the privileged result of price discovery via distributed transactions. Every time in history someone tries to conform the market into an unnatural shape using wage and price controls, the result is shortages and other dysfunctions. The burden of proof isn't on me to show that the market price is the natural one: it's on you to show that in the case of labor we shouldn't have a free market.
You need to show that unions are unnatural before you can claim that they aren't the market price.
* the State, contracts, corporations, right-to-work law, at-will employment law, etc - all good, natural parts of the market.
* employee unions - bad, unnatural, rent-seeking, deviations from the market.
It's untenable.
> It's untenable
It's quite tenable.
No. A union is a group of people saying "pay us more or we'll shut down your business". That's why unions have traditionally had picket lines and why they've historically used violence against "scabs".
We can get rid of collective action for workers when we get rid of it for capital. Until then, if anything we need a shift away from enthusiastically encouraging collective capital while barely tolerating collective labor, to something more equitable and beneficial to the individuals whose government suffers those corporations to exist in the first place, whose interests lie overwhelmingly on the side of labor.