While I agree that the polorized views held by many people obsure the true subtleties of the issues, and that many fail to critically consider their own view point, I would pin the blame of this on human nature rather that political systems. Most discussion of, and research into politics has expanded my horizons, not narrowed them.
I can certainly see your point, however, that those who look without considering can fall into these bad habits. I just think the solution is critical consideration, not avoiding politics.