I understand how you feel.
In the U.S. we have a neat way of avoiding conundrums like this: As a people we have absolutely no sense of history. Anything that happened before our grandparents were alive, meaning we never heard about it first-hand, is irrelevant. Most of us never even heard of it all, especially if we went to school any time since about 1964.
No guilt, no angst, no problem!
Of course that makes us look incredibly stupid when we get a leader who combines our national ignorance with his own personal hubris. Thinks he can stomp into the Middle East in his cowboy boots and resolve conflicts that are older than our COUNTRY? People who had been killing each other for a thousand years or more before his ancestors started giving the Indians smallpox?
We tell the Palestinians that the Israelis have first claim to the land because after all it is their ancestral home and we have to honor that... and the Palestinians can tell us, "Okay Mister Cowboy, then you have to give Arizona back to the Navajo."
No wait, I've thought some more about it and I was wrong. Possession is nine points of the law, that's an abiding principle of our legal system. The Palestinians are there, it's not fair to take the land away from them... and the Israelis walk over and say, "Okay Dude, in that case you have to give Arizona back to MEXICO."
We should stay out of things we're culturally incapable of understanding.
The people who call themselves Britons are actually Anglo-Saxons. Their ancestors stole the land from the true Britons, whose descendants only survive in Wales, Cornwall, and Brittany. But then of course the Britons and other Celtic people stole the British Isles from the people who were already living there, the ones who built Stonehenge.
And who knows how many previous waves of migration wiped out other cultures on "Albion"? Humans have been building seaworthy boats for at least 40,000 years.