The Anglican priest’s discovery of the loss of the knowledge of “Dream time” is evidence of how missionaryism has been the downfall of some extraordinary mental/spiritual maps, and therefore experiences. Ho’oponopono is another.
Okay, I tried not to reply, but I gave in to the temptation.

This line of thought is addressed in a very excellent book called “Truth and Tolerance,” in which Pope Benedict XVI explores the notion of truth, what it is, does it exist, and how does that affect us if it does exist. And is religion about “experience” or “truth”?
If there is such a thing as objective truth, and if one discovers it, and if that truth changes one’s life and gives one unimagined joy, wouldn’t one want to share it? (Witness all the Westerners who go absolutely ga-ga over any teaching that can claim an ancient pedigree, and I speak from personal experience.)
And if that objective truth happened to have been delivered by a religious figure, wouldn’t one want to bring others to that figure? (None of the Westerners I know, for example, who lament the conversion of people to Christianity, lament the conversion of anyone to Buddhism or Wicca.)
And if that religious figure actually commanded his or her followers to go out and spread the word about this truth and bring them to the truth, wouldn’t one want to do just that? (I rarely see Catholics doing this; we’re not known for going door-to-door, but then I don’t remember ever seeing Buddhists do this either. However, both Buddhists and Catholics claim to have found the truth. Well, Buddhism has a slightly different take on what truth is and pretty much denies the existence of any sort of absolute… But both groups, if I may use that word, have made much material available for those who are interested.)
You see, I think what is truly lamentable here is that there aren’t more conversions to the Catholic Church. I don’t think that one should hold to one’s religion merely because of heredity or environment. Lord, I’ve been down a ridiculous number of paths myself, because I was always open to truth, wherever that search might take me.
If one views religion as a mere hobby or a matter of personal taste, then one probably sees no reason to convert to any other religion. Or to
be religious at all, for that matter. But if one sees religion as a way to search for truth, to find truth and to serve truth, then one would surely want as much of the truth as one could possibly lay hold of. So these people who give up one path for another are not losing their ancestral ways so much as gaining the highest truth, as they see it.
And if you really think about it, the whole attitude that they should stay the same as they’ve always been and never change is really rather strange. (I would’ve expected you to embrace the notion of evolution.) I think the aborigines who have converted to Christianity have probably benefited from it. The problems they have are with people who treat them as second-class citizens in their own land–people who just might be much more in need of real conversion than the aborigines are.