We (humans) give our selves more credit than we have earned or deserve, just for being human (people). As people learn to control, and evolve beyond their prideful-ness, their minds and intentions will be clearer towards accomplishing what is best and right for all involved. As opposed to "reacting" as the ignorant and confused.

Lack of continuous learning, gaining knowledge and not being humble are the main causes for the things you ask "why" about.