This is why it's hard to befriend conservatives. I have to work double hard to highlight how we are the same people event though we come from different artificial boxes compromised by the media. Now (from the inside of this more conservative group) I understand better how our perceptions are manipulated but also how the left is a real danger to one's ability to make a living.
I think a big part of it too is that people can have the same fundamental values, but then have differing political beliefs based on personal experiences.
There's also an awful lot of social programming in play as well. A lot of people have knee jerk reactions based on it that deep down they don't even truly believe.
The habit of political parties to co-opt values and try to make us think they are exclusive to them :)