Of course you can assign land ownership this way — it's called an 'ethnostate'. But if you do this, it means that the descendants of immigrants can never truly be full and equal citizens of the land they were born in. If Britain is defined as the land of the Britons, then a Han person whose great-great-great-grandparents moved there from China will exist as a contingent citizen — a perpetual foreigner whose continued life in the land of their birth exists only upon the sufferance of a different race.
