Why do Liberals critisize Fox when CNN and MSNBC are no better?

It seems to me that Liberals, for the most part, have to be right on everything no matter how wrong they may be. I was an independent who became conservative due to the high slandering and persecution of the Liberals im surrounded by. I didnt want to be involved with their "morals" or identity. With every media network leaning towards the Liberal side, why do they get so upset from competition of a non-liberal biased network? Is it not healthy to have fair competition or do they really feel America needs only one political party and become fully communist against free speech? It disgusts me, because in truth all media has bias and all media doesn't always tell the truth or have "great" shows no matter what political party you are. I look forward to the replys - Brandon