So now I am trying to get a plausible explanation for how these 'emotions" could have such a survival advantage over raw brutishness, over good looks, over cunning trickery, over a better coat of fur, over bigger pectoral muscles to kick other sexual competitors asses, and a whole host of other traits to select for.
Evolution isn't about the survival of individuals, it's about the survival or failure of specific gene configurations. Killing everyone else is a good survival strategy for individuals, but terrible for genes because there's no one alive to reproduce with.
Birds of a feather flock together. Do they do it because they believe in God? Seriously, tiny feathered critters work together to protect each other from predators and raise their offspring safely. They don't have enough brain to them to believe anything, they do it because the ones that didn't got eaten by cats and foxes and so forth before they could reproduce a lot more than the ones with the gene configuration and nervous system programming that the ones who flock have.
Southern bigots used to lynch black men just for whistling at white women in admiration. Did they do it because they believed in God? Or was it because that had been a successful strategy for the "honky" geneset for long enough to become common? And did they stop doing it because they stopped believing in God? Or because we started putting them in prison where their reproductive aggression was rechanneled into activities that didn't perpetuate any genes and re-educated their existing children to use their nervous systems in a somewhat different strategy?