This flaw of being "human" seems amazingly similar to the how animals fight and posture over one another to ensure the ongoing survival of their groups and themselves. The only difference is that humans try to justify their motives, where animals simply act. So, are the animals better or worse than us because they don't carry a concept of right and wrong?
And more to the point, why do we care about whether our actions and motives are justified, when we already know our actions are probably going to harm others, anyway? If it really mattered one way or the other, we simply wouldn't act to begin with... right?
The only reason we even bother with such trivial matters as self-justification is due to our fear of the unknown. The big question of what happens after we die... RELIGION!
And you know what? Practically every major war fought here on earth has been over religion!
So, it's no longer simply us trying to console ourselves that our own wrong-doing to wards others is justified... but now we harm one another because one side believes their justifications are greater than the justifications of those on the other side... and as a result, either side's attempt to back down before the blood has been spilled would be interpretted as a weakness of that side's justifications for fighting in the first place.
In other words, both sides must fight because not fighting is far more unjustified than the act of fighting in itself. Most likely, the side that eventually did refuse to fight would probably end up being seen as such a disgrace that they aren't even deserving of life... either to themselves or to their enemy. Those who don't die will probably end up wishing they had... as failing to fight means they abandoned their values to survive.
But while we're entertaining ourselves on this... what's the ultimate solution where no one fights, no one loses, etc.... aka, the path where the utopia is at the end? Do we all network our brains together into one massive hive mind, allowing our individuality to give way to a shared mind that''s been artificially "normalized" by a massive machine that literally polls every human mind on earth over every conflict of interest, and having the majority favored interest become the single interest of every person on earth in one fell swoop, then repeated again and again until we all end up being the exact same person as the guy standing next to us, recurrsively?