As for the CBC - it's not surprising that Harper is trying to shut it down, the CBC does appear pretty left-winged. Of course, the reason they seem so left-of-center is because the Cons have been terrible, so the truth of course will make them look bad. Free press is a cornerstone of democracy though, if Harper doesn't like how he's portrayed in the press he should fix it through his actions, not by removing the press.
Most news sources appear to have a negative bias to whatever point on the political spectrum that the current government represents. The only reason that the CBC has a 'left-wing bias' right now, is because, like you said, the Harper government is so far right. If Mulcair and the NDP were elected, people on the left would be complaining about the CBC's right wing bias.
Controversy attracts viewers. The ruling party dominates the news cycle because they have more exposure. Simple as that. All one has to do is look at the CBC's coverage of the Liberal scandals during the Cretien/Martin years, no one was complaining about left-wing bias then because negative coverage of the Liberal government dominated the news cycle. As soon as the Liberals were removed from power, their share of negative coverage gradually declined as their exposure to the media declined, and the coverage of the then Minority Conservative government increased as their exposure to the media increased.
People complaining about left-wing bias at the CBC are either ignorant of how the sitting government always dominates the news coverage or they're just blindly echoing Conservative talking points without doing a little critical thinking first.
What's important to remember is that if you're on the fringes of the political spectrum, either right or left, everything is going to appear as if it's biased.