You have been asked to repeatedly show some evidence of the decline of modern norms, and have failed to do anything other than assert that things are heading down hill. Do you have any facts to back up this statement?
Most societies around the world and throughout history have stayed fairly close to about the same level of "immorality" there are ups and downs but the mean really hasn't shifted. Every generation bemoans the current generation. It is a self-confirming bias; really good arguments do not start with the conclusion despite what creationism might teach.
As a student of evolutionary psychology one of the main areas that I explore is the development of social norms. Evolution can easily derive moral practices and selfless acts, it is not just about survival of the fittest and moral corruption. Hamilton's inclusive fitness principle showed that evolution could operate strongly to select individuals that help out relatives even at a great cost to themselves. Several modern researchers Cosmidies and Tooby have shown how concepts of "reciprocal altruism" arise under evolutionary conditions in social animals and the types of "innate" morals and ideas that people would develop under these circumstances. Far from dictating an immoral development evolution can program very precise moral standards.
Even if you determine that evolution did evolve a behavior that is now viewed as immoral (violence, rape, ect.) it doesn't follow that it’s our morals that should be eliminated. That’s the naturalistic fallacy, what is does not equal what ought to be. Another interesting perspective on this is that for every time evolution followed a development of some totally selfish behavior others in the social group developed means to counter balance it. Evolution is not one sided both the perpetrators and the victims evolve in response to stimuli. There is no purely immoral development.
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