One of the most interesting debates that occurred during the 1980's was the ongoing debate between Robert Cialdini and C. Daniel Batson. I'm not sure if the two ever spoke directly (I was six years old in 1990, when the decade ended) but I use their names as stand-ins for their respective camps.
Cialdini and his camp believed that there was no such thing as actual altruism--or, more specifically, that altruism itself was secretly the product of egoistic calculations. His arguments depended heavily on the evolutionary zeitgeist of the time, which suggested that for any trait to exist it had to be adaptive towards serving the "survival-of-the-fittest" approach.
Batson and his camp argued that there was such a thing as true altruism, and that we had ingrained impulses and emotions (their prime focus was on empathy) that led us to behave selflessly towards others.
Ultimately we seem to have come down on the side of Batson. What interests me, especially, is that most of the information that was needed to resolve the dispute had already been published in the 1970's by Richard Dawkins when he wrote The Selfish Gene.
The other piece that was missing, though, was the lack of acknowledgment on Cialdini's side that a motive can be both adaptive and not calculated.
I bring this up because I remember living in the shadow of Cialdini's philosophy as I grew up. By my early teens I was already being exposed to cultural messages that argued for the fundamental psychopathy of human beings--the idea that even kindness and altruism were secretly selfish. I found it deeply repulsive even then. I was glad, as I got older, that I eventually found the language to help me not only reject it, but reject it eloquently. I spent a good chunk of time in my Master's program learning to do just that.
Ideas like these have effects. And nasty ones, at that.
(Note that my comment here isn't a criticism of your points here in any way. I love this piece and what you're saying. It's just that your writing reminded me of that old controversy that I wrestled with so much, throughout my life. Some of what you rely on here is based on game-theoretic models and economic theories. They're very useful and I think that they're a great tool for understanding human behavior. But I note also that they take, as their root material, the prevailing philosophical ideas of mid-century economics, which assumed that all humans were rational actors who calculated everything primarily in terms of optimal gain on a set of variables that (surprise!) economists happened to specialize in).
