I'm not sure I understand your comment. If the genocide happened due to diseases imported from the Old World, how is it "heinous"? It happened at a time where people had no clue what diseases and immune systems were.
https://en.wikipedia.org/wiki/Siege_of_Fort_Pitt#Biological_...
As for lands, I don't know, lands all over the world have been changing hands since human beings learnt how to walk, most of the time after violence/war. It happened in 1500 when the concept of "nation" didn't even exist and the only way to say that a land was yours was to be able to keep it.