I'm scratching my head that someone who does security and privacy as their job puts this out on Twitter. Aside from the messed up ethics, it's not a good look while job hunting.

What’s unethical about stating that your entire team was disbanded (aka not terminated for individual performance) and you’d like help with connections finding new work? The message seemed extremely germane, seen those messages constantly over the years.

Agree.

Everyone laid off should be encouraged not judged for sharing the news of their availability with their network, just as much as one might boast when they achieve a milestone or get a new security certification.

And unfortunately ‘I’m searching for a new role’ without context leaves the reasons why open to wild, impersonal internet haters imagination to fill in the blank.

The part where it announces to the world that Patreon is currently running without a security team so they would not be able to respond effectively to hacks.

If your business had a broken lock on the door would it be ethical for a disgruntled former employee to tweet that fact out to the world after you laid him off? They may not be breaking in themselves, but they are substantially increasing the chance that someone else will.

It's the company's fuck up for firing anyone able to respond to hacks.

These people aren't announcing a vulnerability (like in your broken lock analogy), they're announcing that they all got fired and that they all need references. It's also a strong signal to everyone that the company may not be a good place to apply for, for a security position.

Was the employee first fired because of the broken lock?

The tweet says "I and the rest of the Patreon Security Team." That implies that the organization is without any security team or that there could be a lull in capability. Not very security or privacy conscious.