I think if you are asked for your opinion, you should be able to express it freely. And I think if you ask for someone else`s opinion, you should be able to accept it or not ask in the first place. And I also think if you are not asked for your opinion, and you think it may be considered controversial, it may be better to keep it to yourself. And I also wish people would stop trying to involve joint friends in their arguments.
It`ll probably never cease to amaze me how many people seem to disagree.