Here's another datum. We get the same general mix of complaints on SI, where the is no practical limit on the number of boards for a stock and anyone can start a new board if they don't approve of the moderator(s) on the alternative boards. Yet, the complaints of bias (from both "sides") still come despite recommendations to start a new board which, in my view, evidence that the underlying interest lies in silencing the opponents.
That is not to say there are never legitimate complaints about moderators, but more often than not they are simply a means to an end.