I think this is not an uncommon phenomenon, but I still think the more common (and charitable) situation is simply that people don't feel a strong need to expli

I think this is not an uncommon phenomenon, but I still think the more common (and charitable) situation is simply that people don't feel a strong need to explicitly agree with everything the representatives, talking heads, and/or majority voters of "their" political party believe. To be sure, there is a lot of dishonest/self-deceiving side-taking, but a big part of the image of that ridiculous situation is actually just that: An image, conjured by the extrapolation of those observations onto the whole. In general, people understand that a political party is 10s of millions of people, and see no hypocrisy in voting for party A or B without agreeing with all of that party's apparently popular opinions.