It seems that you're trying to make black and white that which is gray. No claims of perfect solutions are on the table here. Only claims of increasingly better solutions. Has humanity solved all of its problems? Of course not! But as an example, our sense of morality HAS progressed from where it was 2000 years ago or 1400 years ago. That is not to say it's now perfect, but there has been progress.
Our environment is different and our morality is different, but there has been no real progress.
In the 20th C we industrialised genocide and saw several of the most brutal regimes in history. Normal everyday people facilitated this. Often well educated. Until the 1980s many Western liberals were still acting as Soviet apologists despite all the evidence by then.
WW2 saw the massive scale deliberate targeting of civilians. You call the killing of a tens of thousands of Hindus, mostly combatants, a genocide and one of the supreme evils of all time despite it being a trifle when compared to the scale of this. We deliberately burned alive hundreds of thousands of women and children and men, I'd rather be beheaded personally.
Even today we don't think twice about 'collateral damage' if there is a 'high value target' who can be droned. At least in the past leaders had to risk their own lives when they declared war on others.
Then there is Rwanda, CAR, Kosovo, Syria, Iraq, Afghanistan, etc.
Technology gives us greater control over our environment and allows us to create societies that shield us a bit from our violent nature. When these societies break down though, we are still the same as we ever were, an uncommonly violent species.
The problem with this idea of progress is that it is utopian (even in its watered down form). It is based on the Judaeo-Christian concept of directional history which is a myth. Everyone before this knew there was no direction, no progress, just an endless cycle of rise and fall.
It is harmful as it teaches violence is a mistake than can be fixed rather than a fundamental part of our nature, just as love or friendship is. Educating us out of violence is the secular equivalent of 'praying the gay away' in its stupidity.
If we accept our nature doesn't change, we can start to focus on the real area in which we can improve things, our environment. The 'least bad' option is creating a society that acknowledges the flaws in our nature and aims to create a society which minimises the chance for these to appear.
The problem is that the 'fixing humans' approach is that it does not do this and often causes greater harm despite its noble goals.
