That might be... it would be hard to test objectively, however.
To demonstrate rigorously whether you are correct or not probably would take a lot of work. But demonstrating to a reasonable certainty whether or not you are correct should not be that difficult.
First you need to think about what you are trying to claim (just as folks trying to take the Million Dollar Challenge do) and write it down more clearly. What are the characteristics which you think are distinctive about the coverage of Republican victories (i.e. what you have informally described as
it's all about anger, irrationality, getting-back-at so-and-so, etc.) and what are the characteristics which you think are distinctive about the coverage of Democratic electoral victories (i.e. what you have informally described as
it's all about peace 'n' love 'n' hope 'n' change)?
Once you have written down the key things which need to be present in a news story to make it fall into one of those categories, pick out some examples of news stories you feel fall into these category, and some examples of stories you feel do not fall into these category, in order to provide a clearer picture of which stories qualify for inclusion.
If you are right in your claim, then it should be very easy for you to find stories about Republican victories which fall into category 1, and stories about Democratic victories which fall into category 2. It should also be very difficult for anyone to find stories about Republican victories which fall into category 2 and stories about Democratic victories which fall into category 1.
For a rigorous demonstration, we'd probably need to agree on a time period and on several media outlets, and go through all the election coverage which appeared in those outlets during that time period to see how many stories about Republican and Democratic victories fell into one, both, or neither of those categories.
But just as Randi starts with a preliminary test which is much less rigorous than the final test for the MDC would need to be, so in politics a preliminary test should in general be sufficient for seeing whether a claim such as yours has merit worth pursuing more rigorously. An informal test -- permitting examination of any news story from any major media outlet which came out in, say, the past 10 years -- should be good enough.
Once you've defined what kind of stories you're talking about well enough that it's reasonably clear if a story falls into one of your categories or not, it should be possible for others to look over various news stories about election results to see if they can find any significant number of stories about Republicans which fall into the second category and/or any significant number of stories about Democrats which fall into the first category. If it isn't possible to do that, then your claim would appear to have merit. But if it is possible to do that, then it should be reasonably clear this is simply a case of selective perception on your part.