There is a difference between independent from an organization, and someone that takes a public stand against a company. Reading that paper, which I am not really impressed with, they are taking a stance that openai's current trajectory is not as good as a competitor. I bet that if a Microsoft board member wrote a paper how Google search is better than Bing / AWS Better than Azure / OSX better than Windows they would be reprimanded also.
A comparison to another nonprofit would make more sense. A board member of the Komen Foundation being reprimanded for pointing out that other nonprofits are far more effective at helping cancer research would be a better comparison.