It's not reasoning, it's basic values. People are made differently. That's why there are political differences between men and women, weightlifters and runners, straight men and gays, and dynamic typing and static typing fans. And you can trace the common reasoning in the baskets of political views. This isn't like some difference between communists and people who would be communists if it weren't for Econ 101. It's differences in regard to questions like whether you're willing to accept that some people will have a worse lot in life. And is moderation in the pursuit of justice a virtue or not?
The moderates are the people whose opinions are most formed from indoctrination.