Throw open the doors to drugs, porn, prostitution and abortion, and if the result is a society that loses its freedom, then it never deserved it in the first place. The world could only help but be improved by its loss.
Arguably, doing away with such moral regulations changes society, produces weaker characters with weaker capacities and commitments to freedom and morality. I think we can all imagine evils that if legalized or allowed on a mass scale will corrupt nations and peoples. Certainly the founding fathers did. Arguing that somehow societies ought to be able to resist such evils without legal restrictions and that if they succomb they deserved to fail is a great display of bravado, but it doesn't seriously confront the question. Legal restrictions are one way that society protects itself.
All societies legislate morality. Laws against murder and theft are legislated morality. I suppose if a country legalized murder and theft and perished it would be an unworthy society whose loss is a blessing. But its unworthiness would chiefly consist in the fact that it had abolished those laws.