Are in fact allowed to not just voice an opinion, but to actually be activists and or paid lobbyist for the copyright industry, and still preside over copyright related cases.
This is a one way street, and the judge has accurately formulated why many think this is the case. We have met the enemy of our freedom and our judicial system.
The "pro-copyright" judges are not biased--they are simpy following the law, which currently holds that copyrights are legal and provides (some draconian) mechanisms for enforcing copyrights. If there are problems, it is not the judges--it is the law.
In the U.S., at least, judges are not allowed to be publicly politically active (except to the extent of their own campaigns for judicial office), or to lobby for political causes at all, though they are allowed to maintain private political views. No copyright lobbyist is a judge, though a few former judges may be copyright lobbyists.
This is not a one way street. The enemy of freedom is not the judicial system; quite often, the judiciary is the primary defender of your freedoms.