There is no going back. There was no going back when the Celts kicked out the Picts. Or when the Saxons kicked out the Celts, or when the Normans overran the Saxons. There was no going back when the second wave of Native americans across the land bridge kicked the first wave farther south and east.
Its happened all across the world, again and again. People get displaced, technology changes, life moves on.
There is no going back, period. Life happens, stuff happens, a country can not be held liable for what happened that many years ago. Times change, opinions change, the way to treat and deal with problems change.
All we can hope is that we are moving forward, and make steps to that point.