Why not, "three liberal Republicans and a moderate Democrat"? Because the writer wants you to believe that a non-moderate is an extremist.
Absolutely brilliant observation. And the creepy thing is, this media-marxism is not a position chosen and advocated consciously by the media drones. It is an implicit worldview, a sub-conscious narrow box that their entire psychology fits within. They are like little bonsai trees, limited by their early limitations, possessing all the genetic capability of their normal relatives, but totally incapable of supplying anything of any value except pointing, laughing amusement.