That's not quite true: Libertarians believe that, as a rule, government shouldn't be used as proxy to force behaviors (with implicit or explicit threat of violence or property-theft).
In the end, passing all sorts of laws will do nothing to address the problem, which resides in the heart — this is because the law cannot save, it can only condemn, and that is the fundamental reason why Jesus came to die for our sins: to do what the Law could not.
Christ is my savior.
Government is not.
Jesus saves me.
Government shapes a better society by favoring marriage as something between one man and one woman, and by declaring abortion to be a great wrong. And in other ways.