Good on them for offering proper severance. At my company, we got 2wks and nothing else. Not even a thoughtful letter from the CEO. Nothing. (And this was a sizable tech company in the middle of an IPO).
There is always a time and place, of course. But generally speaking, you don't speak ill of your (former) employer or even talk about it publically lest there be ramifications beyond your imaginations.
No one disagrees with you in principle, but there are realcitrant social practices punishing this kind of feedback. It is always taken as a grudge rather than an observation, and this makes you less attractive as a hire.
That is to say, (former) employee doesn't speak ill of (former) employer and (former) employer doesn't speak ill of (former) employee. It's how society keeps itself oiled.
He's not burning bridges if he uses a throwaway, or otherwise doesn't attach his name to his report.
But looking at his comment history, I'm guessing he's talking about Tempo Automation (TMPO).