Putting on Blinders: Selective Processes

     So the topic today might ruffle some feathers, but I am going to state upfront that I am trying to remain unbiased in all of this. The theory of selective processes basically states that people's media use will cause them to seek out the information that helps to support their views, opinions, desires, etc. Probably the biggest example of selective exposure is the way people consume media in terms of politics. It seems in politics, especially in election years, people have opinions on everything. Republicans vs. Democrats, Conservatives vs. Liberals. If it has anything even remotely to do with politics, somebody has an opinion about it. I see people everyday supporting their opinion/beliefs when it comes to politics. It can go as simple as someone wanting to get Obama re-elected or being determined to vote republican on everything because they are registered as republican. As the theory of selective exposure goes, these people will seek out the media that helps support their cause, which in this case would be news. Consider this graph:

Original Source: http://www.comscoredatamine.com/2011/03/political-party-affiliation-varies-among-u-s-news-sites/

     This graph shows how the three major news networks' websites are viewed according to people's party affiliation. Republicans tend towards Fox News, democrats favor MSNBC and independents or no party affiliation usually seek out CNN.  While all the networks will try to claim they are unbiased, isn't it conceivable that they may want to skew their coverage to appeal to their largest market in order to keep up their ratings?
     I am not about to say one network is superior to the other, and to be fair I will provide examples of both selectively reporting the news to make it look like what they want (which will support their target audience's opinions). These are commentaries that give full context to try and show the complete story of what is being discussed. Now, let me go ahead and point out before I say anything else that I chose clips that came from the same person to try and eliminate the view that I was using clips of people who were already leaning one way or another politically.
Here is one about Fox News (heavily favored by republicans) tackling the subject of voter fraud:

And here is one about MSNBC (that is mostly viewed by democrats) on Romney's stance on immigration:

     The connection between people's party affliations and where they get their news seems to be so deeply rooted these days that if someone says their party, a person will automatically assume what they watch. I don't agree people should be able to be identified this way, but even I fall into the statistics. I'm registered as having no party affiliation and CNN is the news channel I tune to automatically when I'm trying to find out information.
     I think the most interesting part of selective exposure concerning politics is people's connections to their political parties is reinforced by selective retention. Selective retention states that a person's memories will distort in order to support their beliefs. There is an article that says people's political affiliations are so strong because when people take a side in politics they are essentially adopting a tribe. With the tribal mentality, what the party stands for becomes sacred and its members will support it almost without question. When these opinions/beliefs become sacred, for many they will also become core values that will be shared with other "tribes" they are members of (i.e. their families, churches, clubs). Values are prone to be subjected to selective retention due to they will be biased to reinforce the views of the "tribe" that is bestowing them. This at least offers some kind of explanation to why someone can say they hate a candidate but are still willing to vote for them because they represent their party or how they are a member of a party because their family is.
    In conclusion, let me ask you: in your opinion how well does the selective processes theories hold up? Do you believe selective exposure is in play when it comes to politics? Can someone be identified politically simply by where they get their news? Do certain news networks have a skewed view that supports their audience base, and if so, is there a network that can be considered to be truly unbiased?