Culture in itself is an important difference that makes people a lot more interesting to each other. But the examples given are not the same kind of difference: Olympic swimmers aren't expressing their culture. They're all, by rule, doing exactly the same thing. That the one from your nation does it the best says nothing about your culture, and there's no rational reason that swimmer or you should feel some sort of pride about that.
Some people did. As an example, my grandfather had to fight for the right to live according to his culture, because our country was invaded. Once you fought for your freedom, you begin to feel rather strongly about "nationality", defined as belonging to a group of people that share your cultural beliefs. And yes, you could say he "earned" his nationality. He did not fight in a a war because somebody enticed him to do so: he fought to defend his freedom, his family, and his way of life.
Don't oversimplify those things.
No thanks. Nationality is whose warlords turf you are born on. The second we get over this concept, the world will be a better place.
Thus paving the way for our multinational corporate overlords to consolidate control. Personally I am very scared for the type of global corruption that will be possible without national boundaries.
Your reasoning makes me think of the prisoner's dilemma. Sure, if everyone agreed to just abandon the concepts of cultural identity (leading to nationality) and live in peace, the world would be a better place. But for the moment, I'm afraid that "world peace" is something that only Miss World candidates speak of regularly.
No, it's silly to argue that they are. You've exclusively mentioned virtues that are as common to every culture as they are to every grouping of humans that hasn't been designed intentionally to exclude them.
Culture largely consists of meals, hairstyles and clothing, dancing and mating habits, religion and racism, architecture, crafts, holidays, and nostalgia over mass media touchstones or memories of common suffering due to weather, famine, dictatorship, and war.
When people speak about culture writ large rather than a specific subset, it's usually when they're accusing foreigners or immigrants of lacking "dedication, concentration, work ethic, attitude, [and] family support" or explaining why the citizens of one's own country haven't achieved the "dedication, concentration, work ethic, attitude, [and] family support" of some country with more civil rights, and therefore aren't ready for more civil rights.
It seems groundless and silly, rather than offensive. Examples of cultures that lack family support, a work ethic, concentration, or dedication would make your case.
In fact you have to be blind to not see all of this. Blinded by some touchy-feely wish-fulfillment dream that somehow we'd all get along if we just quit {whatever implausible scenario you want}. I suspect at root its the feeling that we'd all get along if we were all just like me.
But we're not all just like, well, anybody. We're terribly different. Get over it, deal with it, and learn to get along anyway. That's the answer, not blinding ourselves to the astonish variety of ways human societies work (or don't work).
A nationality is a collective endeavour -- it's the people of a country moving the country forward together (each according to his ideas of course). Even by paying taxes and cleaning some beach of garbage, or building a business in your country, you're DOING something.
And people do much more than that, from political action to take down a dictatorship to fighting to keep the nazis out, to tons of other things.
Plus, you don't have to "earn" something to feel pride about it. It just means you love it, and you want the best for it. Do people feel pride about their brothers and sisters? I know I do.
No, but we all contribute to our nation (taxes, labor, voting) so when our nation achieves something great, we share a small part of that success.
Think of a soccer team. Everybody on the team celebrates and feels proud when #23 scores a goal, even though they didn't score the goal themselves. They share in #23's success.
The closest thing we have to a guarantee for human rights is the ability to hold leaders accountable for them, and throw them out on a regular schedule.
So there is still plenty of difference between peoples of the world. Its silly to ignore this.