[snowwrestler]

It betrays a fundamental misunderstanding of the traits related to cognition. Our "selfish genes" do not tell us how to think; instead cognition represents a delegation of authority from the genes to the carrier. We are attracted to porn, yes, but we are also aware that we are attracted to porn. Thus as some citizens descended into opium stupor, others observed that descent and made conscious choices to avoid it. As a result, human society did not devolve into one big opium den. Just like it will not devolve into one big World of Warcraft game.

The real reason we have not heard from aliens is that the distances are physically impossible to bridge.