Each of those employees signed up for a salary and equity.
That equity turned out to be of very little value to them in the end, probably less than they were hoping for.
If they all got paid out anyway, they would not have learned that small equity stakes can turn out meaningless, and that exits are way less profitable for employees then founders.
Some of these employees might now go on to be founders because they learned the dangers of working hard on something in which there is no equity. In the end they might create something of massive value, which the world never would have had if they simply benefited from charity.
I think the lesson of this exit is also more valuable for all HN readers than it would've been if he had just paid out the employees, for the same reasons.
