The people in power go unchecked half of the time by the people of the country that they are supposed to be working for. The politicians are corrupt, and the laws are pushed through with classist, racist (and any other "ist" you could think of) agendas. The only difference between the US and other countries is that we run around the world doing the same thing to everyone else that we do to ourselves.
Or maybe it's just because of Fox News...that's reason enough to hate America, as far as I'm concerned.
In all seriousness though, it's most likely because we never elected Hunter S. Thompson to any kind of political platform. If America was a Gonzo State right now, we'd have another type of image entirely...

^Now that's some shit for the rest of us to follow...
Oh...and America rocks, it's just the fact that some of our people are ignorant, and religion crazed. It's truly a great place though, once you look past those parts that make it not-so-great...