Hmmm. Not really, and besides, who says that supporting homosexuality is "failing moral values"? If anything it shows a culture has its head on right when they are concerned with bigger things then prosecuting a couple of guys who enjoy each others company. And by your logic doesn't that mean that modern society is doomed as well, seeing as how we have incorporated so much of these ancient cultures?
But anyway, as a history student I would be interested in hearing more of this theory, explain how supporting homosexuality led to their downfall, as I have never read a single book that suggests anything like that. Or heard a single lecture to that effect.