C-Span seemed to be the one media form that couldn't be messed with too much because it pretty much let the cameras catch it as it happened. At least that was my understanding.
The specific criticism that I heard was that when they took calls, they had one line for libs and one for conservatives, thus ensuring that both sides were heard. Ann Coulter said that there are many more conservative viewers than liberals so balancing out the phone lines unfairly gave the liberals a bigger voice.
In what other way has C-Span become a tool of the libs?
2. They switch the scedules of conservatives all the time. They especially did this during the 2000 presidiential campaign, when we would all be waiting to see President Bush in a campaiign appearance, and then inexplicably we would get Gore or Lieberman. It happened multiple times.
3. They routinely feature anti-American demonstrations, but will not carry demonstrations in support of the President.
4. Their callers are weighted, as you said, in favor of the liberals. Plus, liberl, Bush-bashing callers get lots of time to talk, while Bush supporters are cut off.
I only watch C-SPAN when they are showing live coverage of a committee hearing or something. Otherwise, it makes my blood pressure go up.
OTOH, C-Span does show the Senate and Congress sessions in their entirety. The SOTU was shown on C-Span without irritating commentary. I think that cable companies are obligated to carry C-Span, so no matter what package you receive, you will get C-Span. And I do like Book TV, which is C-Span2 on the weekends. Lots of interviews with non-fiction authors.
So some of my complaints may just be perception, but I don't think so. I finally wrote to C-Span to complain, they were showing Daschle's press conferences 3 and 4 times a day (while he was the illegal majority leader), and would never run the press conferences more than once, and would cut away a lot.