Better minds that I have talked about the quest for purpose in the absense of faith and I choose deliberately not to endorse any particular moral goal in this piece.
But you did. You said that people should fight against the moral impulse to do good to strangers at their own expense, and strive to ignore their moral revulsion at ill-treating strangers.
selfish utilitarianism (is this really any different from hedonism?) is a good a goal as any although it's not one I personally choose as a moral end goal.
You are advocating it, but not choosing to follow it yourself?
The first person who understood nutrition didn't start on a perfect diet from day 1. Dieting is hard and we're still not very much closer to figuring out effective strategies of subverting our harmful evolutionary preferences. Rebasing ethics is at least as difficult so have some patience while it gets figured out.
Lets start with the following accepted as a given:
Of the current figures who accept these premises, most espouse some form of secular humanism which argues that humans are genetically programed not to lie, murder or steal, therefore this is both the right morality & the one they practice. This, to my mind, is committing the naturalistic fallacy.
Instead, I want to offer an analogy: Humans have an innate preference for certain foods which evolved in an environment radically different from modern society. In a modern society, it is widely regarded as virtuous to be actively working against our innate, genetic impulses through the practice of dieting. Similarly, our ethical landscape is radically different from the one we evolved in. Thus what we should be doing is actively working against our innate moral sense to be more in line with the modern world. In the same way that there is junk food that tastes good but is ultimately unhealthy for you, I believe there is ethical junk food which fills us with a feeling of virtue that is underserved.
Let me start off with a mild example: Tipping.
Altruism evolved in an era of small tribes where individual altruistic acts could be remembered & paid back. Now that we live in a large, anonymous society, there are many times when altruism doesn't pay. Unless you are with friends or a frequent diner at a restaurant or bar, the correct moral move is to stiff the waiter on the tip. If you're traveling somewhere alone, you should universally fail to tip as you're not likely to ever return there.
If this fills you with immediate moral revulsion, you're not alone. I'm so skeeved out by this that I've never yet worked up the nerve to do it. My empathetic system simulates how the waiter must feel to not get a tip and I get queasy in the pit of my stomach. But this empathetic system isn't based on any moral fact, it's simply an evolutionary shortcut that helps us survive in small groups. To rebase your ethics is to start actively fighting against that feeling of moral revulsion, just as the first step of a diet is to fight against the desire for fatty, sweet, salty foods.
In fact, I would go so far as to say that if your own personal moral system doesn't have parts that are morally repulsive to you, then you're not doing it right and anybody who tries to tell you different is selling you snake oil.
As to why I don't hear anyone talking about this stuff, it's like fight club. The first rule of rebasing your entire ethics system is that you never tell anyone you've rebased your entire ethics system.