No, it's just you
Seriously, I do agree that our society has a tendency to dumb things down and to obfuscate the issues with ideology. It takes a good deal of initiative to track down objective and serious information, and a bit of education to be able to distinguish credible sources from biased ones. Most people who get their news from television will be hopelessly uninformed, or informed in the most manipulative of ways.
I do think the things we argue about matter - the economy certainly matters to the people without jobs right now, and tax law should matter to all of those of us who are being screwed while the wealthiest 5% get richer and richer. The war in Iraq matters not just for its own sake or for the immediate consequences, but for the precedent it sets for future administrations considering a "doctrine of pre-emptive action." Iraq is just a great big trial balloon for the neo-cons' bid for American hegemony. At this point, with unipolar dominance, either the U.S. or the U.N. will emerge as the dominator of world affairs, and this administration wants it to be the U.S. These things do matter, and there are legitimate differences between the parties.
In terms of breaking down opinions into two "sides," for some reason humans tend to see all things in binary terms. Two genders. Black and white. Us and them. Tall and short. Thin and fat. Never mind that there's not just a whole continuum of characteristics between the two poles, there is really a 3- or 4-dimensional matrix of characteristics. Too complicated for the 6-o'clock news. Is a parliamentary system with multiple parties any better? It still eventually breaks down into Coalition and Opposition. Two sides. Go fig.
In terms of my opinions being my own: to the extent that any of us have opinions of our own, yes they are. They're informed by my experiences, some data, and some logic. Of course I have some knee-jerk opinions that are just deep-seated biases, but I am willing to hear alternative opinions and if they're sound (backed up by facts, data, logic) I'm willing to reconsider my own opinions. However, few people (as you point out) are willing to argue on those terms rather than on ideological terms that break down basically to "nyah nyah na boo boo, you dirty liberal."
These are really excellent questions you're raising, particularly for this forum where we have a lot of very intelligent people, a lot of very strongly held opinions, and a lot of diversity of viewpoints. It's always good for us to be aware of our biases and our automatic assumptions.