I'm not sure if your referring to New Zealand or not, but the harm was happening in NZ up until quite recently - and arguably still is. I live on land that was once part of a local tribes area, I have dug in the garden and found old shell fish quite deep down in what was once a waste pit. My father has found old adze heads in a relatives garden. I believe that I am benefitting from living where I do, and am more than happy for my taxes to go to those who are descended from those who's land was swindled/stolen from them. The long term effect on a people who's land, lives and social systems have been damaged by colonization is often (always?) bad - and if a small change to me can result in a positive change for them, I don't see the problem.