Now it appears there is some truth to the old joke. Scholars in England tracked the responses of individuals before/after terror bombings that occurred in London. After the bombings, liberals reported more in-group solidarity and less concern with fairness. Conservatives didn’t change along these dimensions.
Much the same is likely going on when it comes to crime. People who are not affected by crime--that is, not connected to it emotionally or physically--are more likely to be liberal. Conservatives, because they see crime as a threat to social order and to individual safety and because they are more emotionally affected by it, are more motivated to control crime.
I’ve always been struck by the number of criminologists who have never met a true thug, who have never been into a jail or prison, and who have never walked the mean streets of a ghetto. There is something that happens to you when you see the suffering caused by criminals--all of a sudden, you become a bit more conservative.