I would argue that it's impossible for government to destroy sexual, or any other element of, morality.
If the population was moral to begin with, they didn't lose their moral compass as a result of anything the government did.
It’s a mistake to overestimate how much the government can do to demoralize a nation. It’s also a mistake to underestimate what it can do. Repealing DADT, for example, won’t make the military gay friendly. NASCAR doesn’t have any rule against gay drivers and the NFL doesn’t have a rule against gay quarterbacks, and yet . . . But the government controls education and much of the nation’s wealth. It can do a great deal to undercut traditional morality. Consider how the Great Society destroyed the Black family in America.