Besides explaining the haphazardness, that would also nicely explain why they didn't want to elaborate publicly on why they "had" to let him go -- "it was either him or us" wouldn't have been popular given his seeming popularity.
Wild guess: If the board stands its ground, appoints a reasonable new CEO, and employees understand that OpenAI will continue to be a hot startup, most of them will stay with the company due to their equity
"Sam was trying to censor legitimate concerns the board had with regards to the safety of the technology and actively tried to undermine the board and replace it with his own puppets."
If that is indeed true they did a mistake by saying something vague imo.