"Justice" is made up by people. For centuries is was justified to conquer and change borders by force. Then suddenly there was a stop ... but all the old borders made by force should remain. That might get questioned again on a broader base, if the borders on a land does not match up with what people think and feel what is right.

So again, why is the amazonian rainforest the property of the brazilian government? Did they plant it? Did they bought it from the people who used to live there? I don't think so. In the end, it comes down to power. Your government might be stronger than the natives living there, but like I said, more people care about the rainforest now, than the people who lived there.