Because anything they say that isn't in line with the rules governing how boards work may well open them up to - even more - liability.
So they're essentially hoping that nobody will sue them but if they are sued that their own words can't be used as evidence against them. That's why lawyers usually tell you to shut up, because even if the court of public opinion needs to be pacified somehow the price of that may well be that you end up losing in that other court, and that's the one that matters.
If it was all about liability, The press release wouldn’t have said anything about honesty. The press release could’ve just said the parting was due to a disagreement about the path forward for openAI.
As a lawyer, I wonder to what extent lawyers were actually consulted and involved with the firing.
So they're essentially hoping that nobody will sue them but if they are sued that their own words can't be used as evidence against them. That's why lawyers usually tell you to shut up, because even if the court of public opinion needs to be pacified somehow the price of that may well be that you end up losing in that other court, and that's the one that matters.