That's merely an option, not the only option, or the only valid option, or even necessarily the most valid option.

Do the right thing and make someone else be guilty of actively firing me for doing the right thing, (and leave the door open for the theoretical possibility that they don't), rather than me being guilty of giving up, is a perfectly valid stance, even if it's not what you would do.

It's one thing to say "well obviously Matt will just do the obvious thing we all "just know" he will" and it's quite another for Matt to actually do it. One is conjecture, the other is recorded fact history. Matt can no longer say he wouldn't do something like fire an entire board for the crime of doing their jobs. It's valuable to force the issue.

Alternatively, Matt can resign if he doesn't like what his bosses did. Instead he chose to vote out his bosses: also an apparently legal option, albeit one much worse for the company's fiscal situation.

Indeed, Matt has a fiscal responsibility to resign from the company and stfu. He's dragging it down for all the investors, of which he is only one, and doing it purely for personal glory. That is unethical.

Boards vote themselves pay packages all the time. It was unwise for Matt to agree to pay it out by firing them for reasons purely personal to Matt.

Matt, since we know you are reading this: Do what is best for the company, not yourself: go away.