From the looks of the OP, it seems to me you’re having a ‘people suck!’ moment.
Maybe we should look at some of what we’ve done before we go blindly building mental monuments to our collective selves. But the things you’ve mentioned aren’t reasons to give up on humanity. They’re insight into the nature of it.
The Bomb (atomic, I take it): A crude application of very insightful collective investigation over a long period of time. It’s a messy way to make use of something we could not have discovered without intelligence, co-operation, and free thought. That its purpose is to destroy is not a condemnation of these things, but a condemnation of the effort we put into destroyinjg each other.
The others mentioned: Examples of how the complex multidimensional matrix of events and states that is human social interaction can be, at some level, understood, and even influenced and used for an aim. Peoples’ behaviour can be influenced into most anything, if they can be made to believe something. So, does the fact that people can misuse power mean that humans are evil? No. It means that some people place their desires and their hatreds before the good of others. We must accept and control this tendancy if we see it in ourselves. Does the fact that people will follow along with things an outsider would find abhorrent if they’re fed propaganda mean that people are natuarally evil? Nein. It means they react to stimulus using the skills they’ve learned in their lives. Does it mean people are too inherently lazy to think for themselves whether something is wrong? Well, are you?
Or, is it a matter of Garbage In, Garbage Out? Maybe propaganda breeds passionate, closed-minded sheep. Maybe being brought up to memorize by rote, to accept what you’re told by authority figures, creates a culture of neglecting to doubt what one is told, if the teller is classed authoritative. Maybe learning to memorize the answers instead of developing the ability to figure them out for yourself leads to a society where people refuse to question their moral structures, and where they believe someone or something to be right or wrong because a text/politician/television/all their friends says so.
Maybe the saviour of humanity is the one who will teach us to think for ourselves, and to question even him. Or maybe the answer not in waiting for the powers-that-be to fix things, but to fix ourselves, and act as examples to others. Live well, by constantly exploring and questioning what it means to live well. Reject the pre-determined for the sensible, and think for yourself. Accept things as they really are, and not as you’d like them to be. Then try to see which things you can change, and how you’d affect all involved you did.
If humanity is lost, it will be because the thinkers were outdone by the passionate, and the sheep ignored what was going on. You can help prevent this: join the fight against ignorance. Practice on yourself. Then practice here. Then take on the world.
I don’t know what to make of the ‘growth slope’ question. We’ve come a ways. We still have a ways to go.