What helped me digest this thought was to consider if Heaven and Hell are not in fact locations or repository for souls but a state of being or existence for ones soul.
Hell is mostly described in metaphors throughout the Bible. It is described as a burning lake of fire. It is described that failure from salvation is ultimately Death. Consider if you die never knowing God or embracing forgivness of sins then your soul burns away, all you know is pain because you arent looking at Love. Your soul dies, perhaps before or after you die.
Consider that everlasting life may be some transcendence of self similar to enlightenment in Buddhism. It is a liberation and freedom.
To know such a thing, to really know such a thing is to embrace it completely. Redemption is a powerful concept. If we are capable of acheiving it then there is hope. If we abstain from judging each other then we focus on judging ourselves.
Its irrelevant what happens to Mao and Hitler.