So true yet humans flock together in groups be it in the workplace, home, government, nation, etc. It's just human to want to be with other humans who share common ground. I feel that going to Mars would probably happen well before any progress is made towards anyone identifying themselves by the world they live in rather than the country. It's so hard to see the big picture in our mere 12 to 20 miles of horizon that we see everyday. The internet has and still is bringing that picture a little more into view but we are a long way off.
One cannot claim that they represent the human race with an American, Russian or Chinese flag being planted onto another planet. Somehow, someway, all we humans need to see each other as the same earthly species, afforded the same inalienable rights. Perhaps it'd take contact with an alien culture before we all start thinking of ourselves as Earthlings and not by race or nationality.