Can you name some examples of these bias issues?
is an example of coverage that comes up if you google it, even Wikipedia acknowledges it grudgingly.
The problem is IMO probably down to the natural demographic of Wikipedia editors drawn to those sorts of pages (cf. academic liberal bias, and - in the opposite direction - the police draw more conservative types).
It's unlikely an easy problem to solve but the point is that Wikipedia is in no position to parade on the issue.