Knowledge comes from many places. You'd be a fool to not utilize and learn from any sources, materials, and yes games that you can.

I'm also basing it on having read and studied voraciously about peoples and their history since I was quite young. I judge people for their actions now instead of their ancestors in the past where the morals of that time instead of ours. It's really as simple as that.

Who are we to judge Shaka, Batu Khan, Cuauhtemoc, etc?