I know nobody wants to hear it. And when the shit hits the fan it's suddenly very real that "evil' people are to blame. And we gotta do something ... resist, fight for freedom etc. But since this question goes deep, the fundamental reason is this:

Because we humans choose conflict/war inside of ourselves every day. We judge ourselves and our actions. We compare, we analyze.

We constantly want to BECOME a better version of ourselves. We feel like we would die if we don't think. We can't just BE. In peace.

We are cute and everything. But push us to the limits of our comfort, our survival and we become nasty. Fear creeps in and we find justifications that we have all the right to protect ourselves.

Peace, like love, is a natural state. It just is when the thinking mind is put to it's right place, and stops being in charge.

And because we can't be peaceful inside, there's no peace outside. The moment we choose to stop making war within ourselves, our world will change.