Even if they don't own it, should they not still fight for it? Is it not their right to murder the descendants of those who live on the land that their grandfathers once lived on?
Let us assume that I live in a country that your grandfather fled. Now you want to move to that country but the government will not give you citizenship. Nor did your grandfather not your father not yourself receive citizenship of the new country you are in, and you were even born in that new country (like your father before you).
What options do you have other than infiltrating my country and killing me?