Why does God give the corrupt people power, so they can oppress the weak:?

He trusted Pharaoh, Hitler, almost all politicians, etc. with power, and they used it, and some are using it currently, to cause strife and sufferings among the weak; and these sufferings lead many sufferers to become cruel and continue to spread conflicts and oppression. Why doesn't God give power to those who want to help others and would devote themselves in his cause?