OK. And yes, these sorts of black and white morality tales exist ... for children. However, the popularity of anti-heroes and shades of moral grey tell us that even older children understand that not everything - in fact, almost nothing - is empirically black or white, good or bad.
We like heroes who face moral dilemmas. We like good people doing bad things. We wanted Butch and Sundance to get away from the Bolivian soldiers. We wanted Han Solo to smuggle stuff and shoot down Empire fighters and bombers. We wanted Wolverine to trash the place. We wanted Gladiator to kick the shit out of the Emperor. We wanted Robin Hood to take Maid Marian (sp?) away from the duly appointed Sheriff of Nottingham, and her maidenhood in the process. We wanted Batman and Spider-Man to kick the crap out of the real villains and escape the vigilante charges against them. We wanted Firefly to outrun the reavers and the central authority to show the people what the real crime was and who did it. We want post-apocalyptic worlds where laws are forgotten and heroes make their own rules, and their own choices.
Perhaps the pendulum will swing back, and perhaps you would be ahead of the curve, but I think that as a story-loving society, we have grown well beyond the simplistic good is good and bad is bad. We know better, and we want stories that don't insult our intelligence.
If the enemy is not redeemable, then it is a waste of space and must be eradicated. Starship Troopers. Lord of the Rings.