Everyone will have a bent in one direction or another. Perhaps be feeling more or less groutchy.
Even a lot of bias shouldn't be a problem as long as individuals are allowed to discuss the issue. If an admin can't support a decision it should be overridden if s/he won't correct the mistake.
I have been overridden after reacting too quickly and I don't mind. I'm glad that can happen since it means I don't have to second guess myself and spend forever researching before making a decision. This takes too much time anyway.
We are here, compared to some sites I've hung around, very, very slow to outright ban someone. That gives them time to learn and change and/or argue with suspension decisions.
The unfortunate fact is that someone unable to follow the guideline about supporting assertions is probably also unable to support accusations of bias or have the faintest grasp of how far off base they are.