He asks a question "why are we doing this" (meaning being completely divisive and hate-filled and such)?
Answer: (and this is a really depressing answer, but it's unavoidable) Because this is who we are, and this is what we want.
"We the People" are not fed, at all, by anything that smells of "the common good" these days. Instead, we are fed entirely by fomented hatred and demonization of the other. We aren't happy unless someone else is having pain inflicted upon them. That's the only way you know that your version of society is working: you see the people you don't like being hurt. We are fed and driven entirely by negative inputs, not positive inputs.
We still hunger for those somewhere inside us -- it's why cat videos and such are popular. But we are now so conditioned to the contrary that there's no f'n chance. The worm does not and will not turn until things get much, much worse, and at long last, we break. But man, the amount of suffering it's going to take to get there....ouch.
Which leaves some of us in a really shitty place. As a first principle, we don't want ANYONE, ANY member of society to suffer/get burned. FFS, some of us have been waving our arms about it for better than a decade. Yet, we've been shown a mile-high stack of plain evidence that the only thing that has any possibility of changing our path is if the suffering becomes too great to bear or accept.....bottom line, we have to get burned. So we're sitting here simultaneously saying "don't touch the hot stove," but also thinking "okay, go ahead and touch it, the pain will teach you that burns are bad when nothing else seems to be able to."