I had a curious conversation when living with an Irish/English flatmate (raised half and half in both countries). He was ranting and raving about people who came back to Ireland and claimed to be 'Irish' on the basis of ancestory. His argument was that you were 100% whatever land you were born in. 'I mean, look at you, for example...' he gestured. 'You were born in Australia, so you're Australian!' I smiled and reminded him sweetly that I was actually born in England, of Australian parents, because my father had a diplomatic post in Vienna. I didn't set foot in Oz until I was nearly three years old. 'Well....' he blustered 'you were raised primarily in Australia!'
Wrong again. I've lived all over the globe, and by the time I was ten had spent more than half my life overseas. New York, Singapore, Vienna, London, Sydney. Both sides of the family are primarily Irish in origin, though, and physically and culturally there's a strong sense of identification there. I like the idea of the 'tossed salad' (or, as I'm ping-ponging around the globe on one of my two passports, I'll tell folks I'm a citizen of the world). If someone has a go at the British, Irish or Aussies, I'll defend them and will usually bring in my background and flexible nationality, but then I'll also defend New Yorkers or other Americans if someone takes a gratuitous or what I feel is otherwise unjustified swipe at them.
I love elements of all these nations and all these cultures, and don't feel that my affection for any of them means I need to exclude 'belonging' to the others. The flip side is, of course, that by not belonging wholeheartedly to any one nation, there's a slight element of alienation...of never quite totally belonging. Or perhaps that's just Aussie, Brit or Irish cynicism showings its colours.
I can understand, however, why people claiming nationality on the basis of a tenuous ancestoral link can irritate the locals. When folks from the otherside of the world, with a highly superficial knowledge of your local history and culture, lob up on your doorstep and expect to be accepted as countrymen and women it can be a bit presumptuous.