Not everyone in a particular group, let's say sitting senators, will always be viewed the same way and will generate the same level of interest. Some by virtue (no pun intended) of their actions in and outside of the job, accidents of birth and other factors simply are more in the public eye. To pretend that each member of a particular defined group is identical to the others is silliness.
If national broadcasters and national cable networks are mass media, then certainly talk radio hosts with hundreds of affiliates and millions of listerners are mass media. That they're not "objective" observers isn't the point; they're mass, and they're most certainly in the media. However, the talk show hosts have no problems frequently holding up individual newspaper articles and editorials as examples of the mass media against which they rail day in and day out. Which is it? Either individual, market-specific news outlets ARE mass media or they aren't. They aren't mass media sometimes--i.e., when they run a piece to the left--and not others--when they run something deemed to the right.