Invention Of A Nationality

Mark Steyn had this to say in regards to Newt Gingrich calling Palestine an invented nationality:

I wouldn’t disagree with that – “Palestinian” as a nationalidentity is entirely invented – and it’s heartening to have it said out loud.

But...uh, technically? Are not all nationalities "entirely invented"?

Seriously, why should Palestine be singled out for this? I mean OTHER than a cheap pandering to Israel moment by the candidates?