I agree with you that legislation alone won't fix social malaise. The first task is to change the hearts and minds of individuals.
Where we disagree, I think, is that I believe legislation can be part of a larger movement of cultural change. The law is a teacher. An imperfect one, yes, but still a teacher.
The primary responsibility lies with parents to form their children in virtue, but I think well-ordered laws can give us a little extra nudge away from vice at times when we need it.