In what way is polarization worse now than it was in the 1960s? I think that the answer has to do with contestable beliefs.
Most beliefs about human affairs should be treated as contestable. For example, would reducing the role of government in American health care result in a more cost-effective or less cost-effective system? I have my own opinion, and I hold it fairly strongly, but I see the issue as contestable.
1. A big reason that I prefer “beliefs about human affairs” to “social science” is that the term “science” sometimes suggests a process for arriving at certainty about issues that I suspect will remain unsettled, such as the issue about the role of government in American health care.
2. Note that my opinion that “most beliefs about human affairs should be treated as contestable” is itself a contestable belief. But I hold that opinion very strongly–more strongly than I hold my opinions about the health care system.
3. I might use the term “sacred beliefs” to describe strong opinions about human affairs that you don’t treat as contestable. For example, suppose that you believe that all adverse outcomes for African-Americans must be ascribed to discrimination and racism. Moreover, you see any questioning of that belief as racist. Then for you that belief is not contestable, and I would call it a sacred belief or quasi-religious conviction.
4. Suppose that you don’t believe that the Holocaust took place. I strongly disagree, and I question your reasonableness, but my belief that the Holocaust took place is in the contestable column, not in the sacred belief column.
5. When you move your opinions out of the contestable beliefs column and into the sacred beliefs column, a number of dangerous things happen. Because your beliefs are not contestable, your discourse no longer takes place in what I call Persuasion Mode. Instead, you turn to Demonization Mode. (See my Cato Unbound essay, Can We Improve Political Discourse?.) You become intolerant. You see disagreement as heresy, and you want to punish heretics.
6. As I remember it, the radicalism of the 1960s did not involve moving beliefs into the sacred beliefs column. In fact, it was more the opposite. There was a sacred belief that really horrible things would happen to us if we another country go Communist, and the anti-war movement challenged that regarding Vietnam, making the belief contestable. There was a sacred belief that if you were homosexual there was something wrong with you (the secular version of this was psychoanalytic), but that belief became contestable. Eventually, a lot of people changed their minds.