In America many students think we fought Russia in the second world war. The fact we fought in Korea would amaze them. But in China many can still see the foreign gunboats on the Yangtze, or grow angry at the sign in a park in a Shanghai treaty port saying "no dogs or Chinese." The Japanese still infuriate many Chinese by denying the Bataan Death March, the Rape of Nanjing and their use of Korean and Chinese girls as "comfort women" for Japanese troops in which the rapes of one woman could involve many soldiers in just one day. The Germans don't have a shrine to their war criminals but Japanese prime ministers have frequently visited the Shinto Shrine which holds theirs.
All of us in the west were complicit in taking Chinese territory and running the treaty ports under English or French law, while Chinese were treated with contempt. The International Settlement in Shanghai was a combination of the America and British concessions, run by the British.
When you see the effort put into the Olympics or the Shibohui (The world expo in Shanghai) you can see the pride in Chinese grow as they brush away the sordid past. Chinese use the words mei mianzi to describe the loss of face (which is the worst thing that can happen in many Asian cultures). When you see Chinese with strong pride in their country, you have to understand they have a right to that patriotism, after all the country's gone through. This is not an endorsement of any government or political party, but simply an explanation of why feeling proud of being Chinese is an important step for a people who spent the early part of the 20th century treated as lesser beings by westerners and Japanese.