I don't understand this point of view. Stock/options are given when an employee works satisfactorily through the date of vesting. That's part of the terms of the deal. Why do you get to decide that a certain period of time before that date, counts as "unfair" if you quit or get fired?
People get to decide because you can't stop them from doing so. There's plenty of situations in life where being right and having a positive relationship come into tension. Invoking the "terms of the deal" usually has a cost, relationally—to the point that choosing positive relationship may be less costly overall.
The person you're responding to doesn't seem to be the founder who wrote the ask HN. Also, the phrase "you're full of bad takes today" seems to be against the site guidelines.
At present he hasn’t been fired and if his date of vesting wasn’t approaching, OPs question may not even have arisen in his mind.
Since terminating him is a question related directly to his vesting, everyone is going to know he was let go right before vesting to eek out the best possible value from him right before he gets something he’s worked a year to receive.
“Yeah but our contract says” is literally the worst thing you can do with a small company if you want morale to be high.
