Watch how the "ancestors from the area" argument immediately vanishes when you tell them this means every single Palestinian who had to flee their homeland since 1948 has a right to return there. These arguments always rest on the implicit assumption that there is a settler class that counts as actual people and a racialized class that doesn't.

Tell them this means they support Russia invading and settling Scandinavia because Russia was founded by an exiled viking.

It really doesn't matter where they are from, ancestry doesn't excuse genocide. You could apply your friend's logic to defending colonialism in Africa, because on a long enough timeline, all humans originated from there, so Europe really had a legitimate claim to those colonies.

Imagine if the Roma people living in Europe invaded Rajasthan, killed thousands, displaced more, and instituted a system of apartheid and oppression on the remaining Rajasthani people. All because the ancestors of the Roma lived there thousands of years ago.