If you see a bunch of negative reviews for a message board and 1/2 the reviews are whining about the board and their admin being "right wing" and the OTHER 1/2 are whining about the board and their admin being "left wing" ------------------ That ought to suggest that USMB is doing free speech and moderation and administration correctly.
And that's the way it is. There are different forums with different levels of moderation. There are forums with virtually no moderation that are "member only". Your content there is never subject to political bias. You just have to contribute to the discussions.
And THAT is probably what all this surprising amount of whining is all about. Don't join if you just want to shout slogans and shut down topics. OR -- if you can't carry on a conversion with "normal" people because you have the focus of a squirrel.