The moral divide in the US was always inevitable as we've moved to a more centralized perspective. I don't think it's a recent development by any means but it is something that I believe is unique to us. The smaller and more tightly wound your group is, the more likely they will all share the same moral compass. Whether that is from fear of authority or something more instinctual, I don't know.
It's all common sense stuff. If you have a larger group, naturally, viewpoints will differ. As the country became more of a federalized nation with a centralized form of media instead of a union of individual states mostly concerning themselves with local affairs, some started to see a change or decline in morality. With the emergence of the internet, panic over the US's moral backbone went through the roof. Suddenly, people with a different viewpoint than your own were there in your home, every time you logged online.
The less we knew about different people and what went on in other areas of the nation, the more moral we thought people were because the only people we knew of, were the ones around us. Now, even though things are more connected, we couldn't be more separate simply because we know how different other people are. They were always people who disagreed and now that geography doesn't seperate us, things are crazy.
That doesn't mean there isn't lots of people like ebenz out there. It just means that they get lost in the noise.