I have read your article again and am substantially in agreement. The Voltaire quote is great, too. But I feel that saying political issues are more complex than scientific issues and therefore people disagree about politics is too ... simple. There are plenty of scientific issues of deep complexity. Typical people who are willing to argue about nationalized health insurance despite a lack of expertise will not argue about protein folding, regardless of the complexity. Huemer argues that people are subject to bias when discussing politics, and they sometimes have good, rational reasons for their bias. I think this is an important factor, and one that should be included as part of the dizzying complexity that makes political questions contentious.
I agree with all of that. I picked the freezing point of water to use as an example, and not quantum theory, for a reason! Much of science is extremely complex -- but ALL of economics is. That's why laws in economics become less reliable as economists try to make them more precise. Great discussion. I hope to hear from you again.