I signed up for this forum specifically to respond to your question.
My response? America went and put a man on the moon because we felt like it.
A more elegant reason is this:
Gordon Sinclair, 1973:
"The United States dollar took another pounding on German, French and British exchanges this morning, hitting the lowest point ever known in West Germany. It has declined there by 41% since 1971 and this Canadian thinks it is time to speak up for the Americans as the most generous and possibly the least-appreciated people in all the earth.
As long as sixty years ago, when I first started to read newspapers, I read of floods on the Yellow River and the Yangtse. Who rushed in with men and money to help? The Americans did.
They have helped control floods on the Nile, the Amazon, the Ganges and the Niger. Today, the rich bottom land of the Misssissippi is under water and no foreign land has sent a dollar to help. Germany, Japan and, to a lesser extent, Britain and Italy, were lifted out of the debris of war by the Americans who poured in billions of dollars and forgave other billions in debts. None of those countries is today paying even the interest on its remaining debts to the United States.
When the franc was in danger of collapsing in 1956, it was the Americans who propped it up and their reward was to be insulted and swindled on the streets of Paris. I was there. I saw it.
When distant cities are hit by earthquakes, it is the United States that hurries into help... Managua Nicaragua is one of the most recent examples. So far this spring, 59 American communities have been flattened by tornadoes. Nobody has helped.
The Marshall Plan .. the Truman Policy .. all pumped billions upon billions of dollars into discouraged countries. Now, newspapers in those countries are writing about the decadent war-mongering Americans.
I'd like to see one of those countries that is gloating over the erosion of the United States dollar build its own airplanes.
Come on... let's hear it! Does any other country in the world have a plane to equal the Boeing Jumbo Jet, the Lockheed Tristar or the Douglas 107? If so, why don't they fly them? Why do all international lines except Russia fly American planes? Why does no other land on earth even consider putting a man or women on the moon?
You talk about Japanese technocracy and you get radios. You talk about German technocracy and you get automobiles. You talk about American technocracy and you find men on the moon, not once, but several times ... and safely home again. You talk about scandals and the Americans put theirs right in the store window for everyone to look at. Even the draft dodgers are not pursued and hounded. They are here on our streets, most of them ... unless they are breaking Canadian laws .. are getting American dollars from Ma and Pa at home to spend here.
When the Americans get out of this bind ... as they will... who could blame them if they said 'the hell with the rest of the world'. Let someone else buy the Israel bonds, Let someone else build or repair foreign dams or design foreign buildings that won't shake apart in earthquakes.
When the railways of France, Germany and India were breaking down through age, it was the Americans who rebuilt them. When the Pennsylvania Railroad and the New York Central went broke, nobody loaned them an old caboose. Both are still broke. I can name to you 5,000 times when the Americans raced to the help of other people in trouble.
Can you name me even one time when someone else raced to the Americans in trouble? I don't think there was outside help even during the San Francisco earthquake.
Our neighbours have faced it alone and I am one Canadian who is damned tired of hearing them kicked around. They will come out of this thing with their flag high. And when they do, they are entitled to thumb their nose at the lands that are gloating over their present troubles.
I hope Canada is not one of these. But there are many smug, self-righteous Canadians. And finally, the American Red Cross was told at its 48th Annual meeting in New Orleans this morning that it was broke.
This year's disasters .. with the year less than half-over? has taken it all and nobody...but nobody... has helped."
(http://www.tysknews.com/Depts/Our_Culture/americans.htm)
Are we perfect? Goodness no. Show me a nation that has done more for the world and we'll talk...
. Feel free to try again though.