> If this is really an existential threat, then it's counter-productive to use as just another political cudgel to score Twitter points on the "other" tribe.

This isn't what is happening. When you see injustice, it's a natural human impulse to get mad and start ascribing blame to particular individuals. It isn't people dishonestly using "just another political cudgel". It's people getting mad, as people have always done, and personalizing things.

That being said, yes, we don't have time for normal human psychology, though normal human psychology is what got us into and keeps us in this mess. Just as it's normal for people to get mad at other people, it's normal for the people accused to get defensive and deny or invert responsibility. "You don't really care! You're just trying to score points! Al Gore is fat and flies on planes!" Both sides are reacting normally, predictably, in counter-productive ways, like the various Palestinian liberation fronts in "The Life of Brian" killing each other in the sewers while the Romans look on in bemusement.