Or maybe they already knew the employees weren't on their side, saw no other way to do it, and hoped a sudden and dramatic ouster of the CEO would make the others fall in line? Who knows.
I'd be pretty concerned too if my CEO was doing what I considered a great job and he was suddenly removed for no clear reason. If the board had explained its rationale and provided evidence, maybe some of the employees would've listened. But they didn't... to this day we have no idea what the actual accusation was.
It looks like a failed coup from the outside, and we have no explanations from the people who tried to instigate it.