Dear Spurious,
I understand your point of view. Allow me to elaborate further.
Now I know that using my own experience is a slippery slope of intellectual disaster indeed. In this case I think it signifies that there is indeed a strong feeling of a 'homeland' in every person.
One of my points would be that this is rather limited to a small local area and local people, such as family, neighbours, townspeople.
Your experience is very much valuable. I agree, I wouldn't feel much when shown a picture of a city in my home country which I've never seen before. But that's not all that makes patriotism.
You were raised to identify not only with your neighbors, but with the entire nation. You celebrated the national holidays, watched parades, learned history. You watched the same cartoons as kids you've never seen, read the same newspapers. Most likely, it was never spelled out that Holland is the most important place in the world. But, through growing familiar with Holland and its culture, your bond with your neighborhood was extending over the country. These are all assumptions, of course, so please correct me wherever you see fit. But this is where the "naturalness" comes in: as one identifies with people, one grows to like them.
In the country where government members are elected, patriotism is crucial. When you vote, you are to think not only of your taxes and your industrial area (for example), but also about the poorer citizens and farmers' estates which you've never seen.
I liked the wikipedia article. However, I've noticed that a lot of people think being patriotic automatically means liking the current government. I think that's a mistake. A patriotic person doesn't have to love the government or the current popular ideology. Patriotism is what would push someone to do something about the dislike of government or ideas. Also, patriotism is not to be associated with ethnocentrism, racism, or anything of the sort; these are different things. Yes, you may think that immigration is bad for your country for some reason; indeed, some think immigration is bad for economy and those who occupy low-paying jobs. But this in no way implies that people from other countries are inferior. When it comes to international relations, the country in which you reside ought to be the most important one, because its government represents your interests.
Yes, it is easy to promote patriotism and turn it into fanaticism. It's easy to do that with any emotion or reasoned conviction. It's easy to make a fool out of anyone this way, not just the masses. But here comes the responsibility of each individual.