The board may have been incompetent and shortsighted. Perhaps they should even try and bring Altman back, and reform themselves out of existence. But why would the vast majority of the workforce back an open letter failing to signal where they stand on the crucial issue - on the purpose of OpenAI and their collective work? Given the stakes which the AI community likes to claim are at issue in the development of AGI, that strikes me as strange and concerning.
I expect there's a huge amount of peer pressure here. Even for employees who are motivated more by principles than money, they may perceive that the wind is blowing in Altman's direction and if they don't play along, they will find themselves effectively blacklisted from the AI industry.