My reasoning is two fold - I haven’t shared anything that could be exploited by anyone. And second, Meta and others in the industry try to share information about how their integrity efforts work so we can learn from each other.
“Legal peril” and “I think” are not compatible, for a rational person. “I know” is where you want to be, before putting yourself in front of one of the largest collections of lawyers on the planet.
This is not some general blanket approach you can take to talking about internal implementations. You are either right, or wrong. There is no middle ground or "I think". If you've signed an NDA around these internal implementations I would wager that NDA came with a clause to not discuss it without consulting Meta, even after your departure.
And it's obviously BS that companies can abridge a citizen's freedom of speech after the employment agreement ends. If this individual wants to be the case on the lawsuit that's a long time coming, more power to them.
This Supreme Court is not big-tech-friendly; good time to shift up the precedent.
Have you never seen https://engineering.fb.com/? Engineers there blog about their tech tools all the time. "Legal peril" sounds like a bit of a stretch.
These posts are all thoroughly reviewed by comms and legal teams. In onboarding, it’s thoroughly communicated that you need to go through the proper channels to publicly publish anything with technical details.