I think that anti-Americanism is half true and half another stereotype. As I see things, the US government is very hypocrit. On the one hand, they promote freedom and on the other, they close their markets and pass protective laws. I am also from those who agree that both the attack to the World Trade Center and Iraq were planned to have an excuse to attack and get oil reserves. Actually, Osama Bin Laden's video two days before the re-election of Bush was more than suspicious for me.
From the American people I have met, I'd say you are kind people. The problem is just that: you are perhaps too kind. It seems your culture is so civilized that your lives lack the passions other people have to live with, like, for example, when you struggle daily to eat or not to eat. So how do you inject some passion to your lives? Through your very developed, but also very stereotyped, entertainment industry. The problem is that when you sell your TV shows and films (British English, sorry) to the rest of the world, it is this stereotyped view what we see. Friends, Sex and the City, SmallVille, Ally McBeal... you name them.
A third ingredient would be your Paris-Hilton-styled individualism and materialism. American culture was born with the philgrims (sorry if misspelled) who you remember in your Thanksgiving Day. They were the Calvinists that were escaping from the English queen's Anglicanism of the time, and they were people who believed in predestination: God already knew if you were going to Heaven or Hell at the end of your life, so the clue for them was success in life. Now you live upon those principles: striving for more success and striving for being successful for yourselves. It's not "bad" nor "selfish" because you were raised under those cultural principles; however, when you see it from another point of view it is just a selfish way to see live! So I think this is the third source of anti-Americanism.
Actually, Inca's policies included sharing a lot and here in Peru you can still see people sharing food if the others are too poor. You wait for the government to provide you with the stuff you need if you have an emergency.