We know so much about so many things, yet we continue to embrace the same political insanity responsible for so much suffering. Why? To what end?
We have evolved free will, self determination based solutions to all the problems we historically have confronted, that harmonize with our nature and the laws of the natural world, yet so many choose darker paths of self indentured servants to a all powerful oz.
We see over and over again what does not work and yet we must continually fight against those who would repeat those same societal failures again and again. Why???
I think the answer to your question is that evil pops up over and over again and must be conquered yet again.