Well, because, for any of you ultra conservative Christian that come here: A Liberals open-mindness does not mean anything goes. For example, we're totally against your church taking over, even Catholic Liberals are against your church taking control of all because history shows us what that does. Shitstorm being a proper subtitle of any theocratic history.
On the other hand, you could be full of stupid deluded ideas that would effect your open mindness, like everyone should have a gun, churchs should be in charge, Duck Dynasty displays good role models and the 50s were wonderful for everyone. And you could say (as Conservatives often do) that when people disagree with you that they're close-minded.
So No, It's not a virtue persay because open minded (and close-minded, and Liberal) is a relative term and the values and scope of it change with every person.
In other words don't use such broad labels then try to lock a specific definition on them. You pretty much have to find specific groupings of a mindsets or dogma to attach labels.
It's been proven here by fundies that they're pretty close minded on the Biblical stories, they accept them on faith, they also believe in phychics, ghosts, good luck charms, conspiracies, curses, and a multitude of whack-job media clowns.
