Fairness, Or Might Makes Right?

Suppose your group of people came to another land and replaced the natives there, with some of them consenting, and some of them not consenting. Suppose the natives there were replaced due to a variety of factors, such as disease, or a culture that did not promote productivity as well as that of the replacing peoples. Is this fair? Or is this simply right by might, and possibly evolution?

In case you think I'm talking about the migrant crisis in Europe, I'm not. I'm actually thinking of the non-native settlement of the Americas and Australia.

Think about it: did the Native Americans and Australians deserve to be replaced? If not, should the Americas and Australia be given back to them, and the non-native descendants sent back to Europe, Africa, Asia, etc? Or was the replacement of the Native Americans and Australians simply part of the evolutionary process?

Could it then be said that legal and illegal migration into the US of Latinos, who as a group are genetically closer to the Native Americans than any other group, is justified by fairness, or right by might?

Does morality matter in any of these scenarios, or is it all just right by might?

In either case, consistency matters. Morality can't matter in select cases, only to be thrown out the window in other cases.

Thus, I fail to see how one can justify the replacement of Native Americans and Australians by non-natives, while disagreeing with the replacement of Europeans by non-natives, both in Europe and the US (where they aren't even native anyway). Either both scenarios are unfair, or both are justified by might making right (evolution).

And don't tell me one group is simply more deserving than another due to their past contributions or charity. There is no point in harping on about a glorious past. Only the present and the future matter.