It was a peak of humanity, as you note; one in which those ruling considered themselves to be gods and subjugated entire races through force. If a war was won, the conquered tribe or nation was enslaved. Most often the leaders of the conquered nation were slain; many in a most vicious manner in order to accentuate the dominance of the conqueror. Women were considered inferior beings and not even counted. If a slave died it was not mourned, it was merely replaced. The idea that a slave had equal dignity as a person to that of his owner did not exist. There was no distinction made between person and station. Power was absolute and unquestioned. There were no elections to temper a dictator’s actions – they did as they pleased and whatever they did was considered right because they did it. Any public insurrection was dealt with by an obedient armed force. Nuremburg could never have happened in those times. Different tactics were necessary to impress the Pharaohs and Caesars than are appropriate in today’s western societies. Similarly, the Aztecs had an advanced civilization; one in which they sacrificed children to appease their gods. If the groundwork had not been laid by the Israelites and Christ had not been born there would have been no Virgin Mary of Guadalupe to convince the Mexican natives to stop their sacrifices and no Church to explain what the apparition meant. It seems to me that progress is being made.
If you decide to judge all of God’s actions from the perspective of today’s norms you will continue disagree with them. His actions must be viewed in the context of the times during which they occurred and in the context of eternity. We will never, in this world, fully understand the actions of God. If we view the acts of most historical leaders through today’s morality they will appear ruthless and unjust. If one does not understand the brutality and determination of the Japanese army during WWII; the ruthless way in which they treated the conquered nations, the casualties endured by the allied forces for every acre of land retaken, the willingness of Japanese soldiers to die for their emperor and their honour; Hiroshima and Nagasaki are hard to justify. No reasonable person would suggest dropping nuclear weapons on Japan today – does that mean that it was immoral in 1945?
If we remove eternal reward or damnation from our examination of salvation history we also stand little chance understanding it. Our ultimate purpose is to return to our Creator and if we do not accept that destination we have little chance of agreeing with the course that is taking us there. Everything from the beginning of creation to now is part of a journey to where we are going. If we look at a point we passed through in our travels from where we are without considering where we’ve been it’s unlikely that we’ll understand why we needed to be there. If we don’t consider our destination, none of our journey makes much sense.