My wife works for a local TV station, and she has to put up with Pete Jennings' utterances. Whenever Pete shoots off his mouth the phones light up--"I'm never watching your station again!!"; "Why do you people let him get away with that!!". Truth be told, the local affiliate would love to do away with ABC Nightly News, but they can't for obvious reasons.
So why do people continue to watch it? Probably out of habit. Network news is mainly watched by old folks that grew up with pre-cable television. My parents fall into that category. The majority of people that call my wife to express their outrage are senior citizens.
Why do our intelligence agencies monitor Al-Qaeda, etc?