Much of the support for gun control is not utilitarian or instrumentalist in character, Gary Kleck explains:
That is, many people support gun control even though they do not believe it is an effective tool for reducing violence. Instead, positions on gun control seem symptomatic of culture conflict, with gun law used as a way of declaring gun ownership and gun owners to be morally inferior, parallel to the way alcohol prohibition was used as a way for older Anglo-Saxon Protestants to condemn the culture of supposedly free-drinking Catholics from Irish or Southern and Eastern European backgrounds.
(Hat tip to Peter Taylor.)