I've noticed (and it is well documented) for example when right-wing think tanks etc are cited or quoted by the media, they are actually labeled "right-wing" or "conservative" most of the time, while left-wing institutions are called more generic and complimentary names like "consumer advocate" or "public watchdog" etc. Also, left-wing radicals are more often than not labeled "activists" or "protesters", while right-wing zealots are called the more negative descriptions of "extremists" or "zealots". Often when covering right-wing people and institutions, financial and business connections are immediately detailed to show an "inherent bias" or "self interest" or "hidden agenda" angle, while the issue of where the purse strings manipulating left-wing "puppets" originate from are usually not disclosed or examined. This is especially true in environmental news coverage.

The fact is the mass media is generally liberal and THEY ARE NOT AWARE OF IT. They are surrounded by other jounalists, editors etc who share mostly liberal politics. Liberal is the norm to them in and out of their work environment, so they think this is the norm for most people. When they encounter a "foreign" viewpoint, they wil instinctly feel it is "fringe" or "extremist", that "normal" people couldn't possibly believe such "strange" notions. It's just the way things are. It's not a conspiracy or anything. Thank God for the internet to express all viewpoints.