The same way there's a big difference between firing a government employee and expulsion of a member of Congress.
In a semse board memebers have even less protection than rank and file. So no, nothing special happening at OpenAI other than a founder CEO being squezzed out, not the first nor the last one. And personal feeling never factored into that kind of decision.
Substitute "rules of order" or "parliamentary procedure" if you like. At the end of the day, it's majority vote by a tiny number of representatives. Whether political or corporate.