What I used to not understand about tribal politics is, if you're of the belief that everyone on the other side is ontologically evil, and there is no act you could commit against them which is immoral, why lie about what happened, rather than simply say "that bastard fought back while getting hit by that car driven by one of us!" rather than all the rationalizing and mental gymnastics about how it was an unwarranted act of murder, then I realize that all the lying is nothing to do with fooling the opposition at all, it's to continue misleading members of the in-group who might defect otherwise. The seemingly narcissistic need to paint oneself as a pure good while the enemy is the ultimate evil is necessary to keeping the tribe cohesive, and whenever the opposition approaches with the actual truth it's dismissed as a lie because the truth came from the enemy, who is ontologically evil, so nothing they speak could be truth. The liars of these in-groups are the real evil, and the people who believe them are useful idiots.