To paint the surviver's assessement of their own carnage as ignorant is just odd to me.
There are two tpes of ignorance at play concerning their understanding of events. Lack of knowledge....not their fault, but as you say in your post sab, pertains to the knowlegde of our day. And the other was that they didn't understand so they attributed it to a god....that is still the case today in many religions.
I know as a believer I attributed everything to God, or at least 'his' understanding as I perceived it. But that was not honest on my part because I really don't have an understanding of God/gods....and I'm not sure it is possible considering that vast amount to choose from. So now I choose not to attribute things to god that I don't understand...including 'evil' because that also is unproveable in my opinion.
Evil is just a way of labelling and encompassing behaviour...I prefer to decide if the behavior offends my senses or not. And to be honest...this opinion can change depending on what I learn. For example...as a 'christian' I believed that homosexuality was wrong...so it probably could have been classified as 'evil', but now that my brain is not so switched off...I realise that that opinion in itself could be considered 'evil'. Since I don't consider myself an evil person...I can only conclude that I was misguided and ill informed....ie ignorant.