I imagine if you talk to the average American about China their comments will mainly be dictatorship, death penalty, abortion, tanks running over people because they love democracy and other Cold War relics of political thinking. If you were to confront the same person about the Pullman Strike or the Great Railroad Strikes of 1877, talk to them about libel and slander laws prior to the 20th Century, political machines, or get into discussion about the chain gangs they’d look at you quizzically not grasping that these were all parallels to present-day China in 19th Century America.
Indeed even those who know about these issues would probably not be able to lump these in with Jim Crow laws, Indian Wars, and child labor and see a complete picture of 19th Century America as a corrupt, authoritarian nation with little respect for the freedoms it so proudly triumphed.
People hold rather idealistic views of Lincoln, who believed black people should be rounded up and deported, and John Adams who used the Alien and Sedition Acts to arrest his political opponents. They don’t talk much about the part of the American Revolution where militias massacred Loyalists and extra-judicial killings during war being the real source of "lynching" but are instead given a very limited and indistinct view of American history, often with a fair share of political spin to diminish the importance of the less appealing parts.
At the same time that people lack this ability to relate China’s current circumstances to our past they’re made ignorant of other issues in China. The labor contract law, for instance, is probably not something most Americans know about. People’s understanding of China’s present situation, China’s history, and the complete views of Chinese people leads a great deal to these problems. People probably aren’t told of T i b e t as a feudalistic society where people’s hands were chopped off for trying to run away from the noblemen. It’s not taught as a place where people were effectively put into slavery and children forcibly put into monasteries. They don’t talk about the rule of oppressive nobles and secular military leaders. They don’t talk about their lack of belief in the death penalty but how they would just leave people out in the Himalayas at night and "leave them to god" as punishment.
Basically Americans are spoonfed a lopsided view of the world and up until recently they would have to scour the globe to come to any sort of complete understanding of the circumstances in China and the United States. Part of it was Cold War propaganda but another is just a typical Western misunderstanding of China and the Chinese. So if you run into any people who are overly hateful, it’s probably just a result of this complex problem.