Forget right wing and left wing, the bias is about sensationalism. They will tell you what ever story leads to more advertising revenue. And who will stop them? The news casters? Not a chance. They are chosen based on boob size and tooth straightness. Outside of "The news hour" and to a lesser extent BBC news, there is no legitimate TV news.
The loss of real news sources has to be one of the greatest current threats to our democracy.