In the long run, perhaps a shift towards "advantageous to the survival of the largest percentage of the population" is a shift that's been happening, well, forever. Some ideals that were popular and widely accepted as "good" decades ago are no longer seen as advantageous, so slowly, over time, they've fallen out of fashion. Just look at slavery. It used to be widely popular. Now, it's a fringe behavior, because a large portion of the population finds it barbaric. There's another fringe that believes that owning a pet, regardless of how well cared for the pet, is abusive. That's, pretty much, our current spectrum of beliefs. And that's how evolution works.