Obviously, Microsoft has some influence here. That's no different to any other large investor. But the key factors are:
1. Lack of a good narrative from the board as to why they fired Sam;
2. Failure to loop in Microsoft so they're at least prepared from a communications front and feel like they were part of the process. The board can probably give them more details why privately;
3. People leaving in protest speaks well of Sam;
4. The employee letter speaks well of Sam;
5. The interim CEO clown show and lack of an all hands immediately after speaks poorly of the board.