There is one thing which the human species excels at, and that's tribalism. We with our ape-brains like to think of ourselves nowadays as "civilized" and morally advanced, when in reality every single one of us could and does turn into a warmongering, xenophobic piece of shit when exposed to the right ideas and environment. Dehumanizing other groups is our favorite past time activity, as evidenced by the rich tradition of warring, pillaging, raping, and subjugating we humans carried out for millennia. The empathy we feel for our fellow human beings is not a fixed constant in our psyche, rather it's an optional function that can be turned off at our convenience. Even today you will find plenty of people publicly cheering for the atrocities committed by their forefathers, because as long as a catastrophe only concerns those who are not in our respective in-group, no one gives a shit.
This behavior is inherent to our species, in so far as that the seed which leads to this way of thinking is present in all of us. We as a collective are a ticking time bomb. And contemplating the bleakness of this reality is some top notch suicide fuel, if you ask me.
I know it's a bad rant, just needed to vent a bit.