When you get compensated by the company, you become a consultant of the company, which is a level below being an employee, an insider.
That's fair game on a board. You are being paid to be there. That changes the entire dynamic of the discussion. It's the same thing as hiring a PR firm and scrutinizing their past. Only difference is they are a 'firm' whereas, you are a 'person.' But that doesnt mean anything. Just different roads to the same Oz.
However, there is still a line to be drawn at some point.