In my experience, early employees at startups don't usually just work from nine to five. They usually _do_ make large time sacrifices. I would say that early employees generally _are_ entitled to a fraction of the profits.
A: Fair market rate hasn't been fair for a while, due to non-poaching agreements.
B: Nevertheless, "fair market rate" typically includes gaining equity over time at a company. More equity the younger the company is and the more it is growing while you're working there. If you work for "fair market rate" at Microsoft, Google, Amazon, Facebook, etc. you get stock grants, stock options, the whole nine yards. If you work for "fair market rate" at an up and coming startup you'd expect to receive stock as well, and in comparatively larger chunks.
In Minecraft's unusual case, it was already seriously de-risked when the first few employees were hired. The additions however, did keep the momentum going, and deserve a cut for that. Jeb immediately comes to mind.
I'd agree it would have been nice to have given at least some stock options to employees. The $300k bonus for staying 6 months, though, is a lot more than what one should expect to get when joining a startup. (Zero would be the usual amount because most startups fail)
They signed a contract. They made a deal to work without having that kind of cut.
We can enter in the sympathy realm after this, but no one was entitled to anything. If they didn't like the job, or felt underpayed, they should've done what everyone else does: Try to find a comfortable solution with their company, and if that doesn't work, leave and find a better job.
I see you are part of the "written word only" style of ethics. This is where you declare only those things prohibited by written law or contract to be unethical, and then grant inventive persons the status of geniuses when they find new ways by which to exploit you.
I am not, and despise exploitative use of law. I believe human behavior is so complex, that defining what is acceptable or not in paper for all the possible cases is borderline impossible. Written, clear laws have their place, as does human judgement.
That being said, it really seems clear in this case.
Compensation for work is one of the things defined at the beginning of a work relationship, comfortable for both parties. Minecraft was already big when anyone was hired, I assume that if any extra compensation besides salary was expected, it would be asked for when the work started. Disgruntlement seems a bit out of place, and seems to be used in the piece to adorn a non-story.
Plus, note that my course of action would be talking to your employer to try and find a solution that works, not just "suck it up".
