Well the aztecs did the same before the europeans:

"Before the arrival of Spanish conquistadors, the Aztecs eradicated many Mayan works and sought to depict themselves as the true rulers through a fake history and newly written texts"

https://en.m.wikipedia.org/wiki/Maya_codices

I dont mean this to be taken as a justification or something, but there is this tendency of picking historical eventsand judge them by todays standards, and is particularly egregious when it is only applied to just one side portraying others as innocent victims when they were actually doing the same thing.