Well, think of it this way: the only thing that other countries' citizens hear of the US is through the media, and what does the media report on? Stereotypes, suffering, misery, basically negative things. That's all the news is anymore is negative. Also, you have to take into account that as a populous, the US is probably one of the most diverse countries in terms of culture. And since there is a limited space to abide by, many of these different cultures cross and form conflicts. One culture believes this should happen, or another culture thinks this should be law. It's just back and forth arguing that essentially becomes a way of life over here.
And quite frankly I think that because there's just so much negativity thrown onto us as a nation anymore, that the average citizen just doesn't care. We don't give a shit what you think about us because we're constantly assaulted with it on a daily basis. It's 2011, almost 2012 and yet we're still being blamed for things that our great grandparents, and our grandparents had done. Honestly, I'm just really tired of it. I'm tired of being looked upon as the bane of the entire world because of the narcissistic, greedy dealings of our government and the fucking fat cat businesses that rule over us. Honestly if you guys from other countries want to call me stupid, fat, greedy, ignorant, and all those other stereotypic words, try putting yourself in my shoes (a common citizen, or essentially a "nobody"), where even though I live in one of the wealthiest countries in the world, I still have to worry about whether or not I'm going to live past 35, whether or not I'll have enough money and resources to support myself and my future family, and whether or not I'll be able to get a job despite the fact that I have a Masters degree (plus hoping that others out there will be able to look past gender and race stereotyping and similar bs).
This isn't just an "American" thing either, I'm pretty sure these kinds of things are occurring right now in countries with enough economic presence to have divided socioeconomic classes. Honestly I would have hoped that we as a species would have grown out of this petty hatred, but alas as long as there is money to be had, there will be conflict.