Why are liberals typically very good at making decisions based on facts unless it regards gun control?

Although my views are probably mostly conservative, I refuse to identify myself with the Republican party since it has become a joke in the last couple of years that seems to be proud of its own ignorance. My assessment is that liberals are usually much better and making non-biased decisions based on facts unless it comes to gun control. There is no evidence that gun control laws correlates to crime rates. Why is this such a hard issue for liberals to compromise on. Is it just a cultural difference since most liberals were not born and raised in the Midwest where guns are ingrained in your daily life?