In this case, it is not entirely voluntary for the employers either as they need employees for their business to function.
> but ultimately I'm going to have to choose one of them
No, you can become your own employer, for example.
> There's a power imbalance between employee and employer, and that will translate into a negotiating disadvantage
It depends on the state of the market. Right now, the job market is supposedly very good for programmers (employees).
Employers are offering to trade their money in exchange for other people doing some task they want done. If you do not think it is fair trade, then do not do it. You are allowed to grow your own food, or pick berries.
> No, you can become your own employer, for example.
Not without capital, and you generally get capital by already having capital (collateral).
> It depends on the state of the market. Right now, the job market is supposedly very good for programmers (employees).
Good for programmers! But in general, the job market is not as good for most people as it is for programmers.
> Employers are offering to trade their money in exchange for other people doing some task they want done.
Right, this is a "voluntary" transaction entered by both people, but the argument is that there is a power imbalance that influences this transaction and tips the scales toward the employer (in the general sense, I'm sure we can find single examples where this is not the case).
Not only this, but the balance is tipped even further by a system that overwhelmingly encourages debt (yes, voluntary, I know, but socially involuntary), essentially shackling people to needing higher amounts of income (and therefor relying on their employer more).
It's possible to be debt-free and have a high-paying job, but it's exceedingly difficult, and you're essentially limited to a handful of industries.
You're also free to die in the gutter, don't forget that one.
Regardless, both parties are made better off by the trade. Employers are the ones helping those unfortunate people avoid the thing that is even worse than having a job, such as: suffering and dying in the gutter. :)
Which is why the saying “strength in numbers” is a saying.
Most people would simply prefer a raise at a job they love---
The job provides health care and covers housing cost, and retirement pay. The job can short you and thus you look for a side hustle.
But people also look for a side hustle to move up to the higher side of where they are in the class scale, or find retirement safety.