First off, let me say and establish that I am a proud American-born adult. I have pride in my country, and faith in its leaders. If you don't like that statement, you can stop reading right now.
The world today is one big Hollywood show. We have the nations that are superstars on our planet, and then the ones that bust their asses to try and make ends meet. Think about it, America is that "superstar" amongst 200+ nations scattered across the Earth. We are the land of the free, home of the brave, the world superpower.
In response to the first part of that question though, America cares about the world a little too much in my view. As an avid Hollywood star always has to be under the spotlight, our country does the same. Everybody knows about us, everybody has heard about us, everybody knows what our country stands for. We are in practically every nation in some shape or form, whether it'd be through the Peace Corps, or our Armed Guard. We're everywhere, trying to help everybody and be a guardian to the struggling nations. If America didn't care, why are we in our war against terror? Why are we going against Iraq? Why did we ever go into Somalia? So no, I disagree with the fact that America doesn't care. It is because of America that Israel exists, it is because of America that people around the world can eat under the sign of a red cross. That is only a microcosm of what this country does for others.
The second part of your question talks about the fact that when we get hurt, the world sympathizes. That is true, and let me take you back again to my Hollywood example. Now, Winona Rider just got convicted of grand theft and vandalism in her Saks Fifth Avenue shoplifting case. Take a step back for a moment, how many people steal every day? How many people vandalize? There are too many cases to count, right? Now how many of those people get trials for what they have done? Close to none. Now, Winona got her case, and the whole nation turned to her, and many of them sympathized with her, saying that there was no way she could have done it. Bottom line is, when a "celebrity" gets defamed or injured, the whole world puts its eyes on them. However, nobody takes the time to look at the millions of people that suffer the same fate, but don't carry the title.
It's a bitter truth that we have to live with every day. It's something we can't change, and if we do try to change it and succeed, than that is for naught because you become the celebrity yourself. Once you start getting all the attention, what you fought against, you now become.
Another bitter truth that many people in this so called united nation don't understand is how other nations look up to us. Because of the previously stated fact that our country goes out of its way to help causes around the world, we are looked up to. When somebody you look up to is hurt, they don't ask for sympathy, you give it to them. You want them to get better, you want them to survive this little problem and move on. The same thing applies to when we as a nation were hurt.
It's funny how we call ourselves "united." When in reality, we're severely divided. Look at Iraq for instance. That nation hates us and will hate us to the bitter end. They are united in what they do; they want to get rid of us. Then look at us. The polls the media holds, the Americans who want to behead the President, the protests, the riots, Americans who don't give a crap what happens to our country. You call that united?
That last paragraph was more of a rant than anything else, but it still applies. This question and other questions like it are controversial, and I know about 50-100 people who won't like my view at all already. That will cause chaos within itself. But all in all, these questions are always fun to answer, mostly to see what the reactions of other people will be. Thanks and take care.