I think that most Chinese are patriotic, just as Americans are. However, the average mainland Chinese I've met is way more patriotic than say your average American or European or even Japanese.
Here are some examples:
1) As others have said the mainland Chinese are taught from grade school about the wrongs committed against China (eg. Opium War, French-Sino War, Sino-Japanese War, Russian land grabs, WWII, etc). Given the fact that at one point, China was carved up like a melon by the Imperialist countries I don't blame the Chinese for distrusting the West. But because of this legacy, the average Chinese feel that when their government is attacked (such as on its human rights record), they take the attack personally as they see if as another attempt for foreign powers to meddle into what they feel are Chinese internal matters.
2) The leaders of China's communist party are revered like gods. In fact, Mao can almost do no wrong. I had a friend who taught college age kids English in China. He mentioned that every conversation ultimately ended up about Mao. One conversation about cigarettes digressed into whether China would have been better off had Mao not smoked and thus lived longer versus the fact that the cigarettes relaxed him and made his decision making that much clearer. To the Chinese, Mao is George Washington, Abe Lincoln and Jesus all wrapped into one.
3) The Chinese government actively encourages Chinese media to focus their attacks against foreigners. For example, when I was in China the media reported about how a construction company found a stockpile of mustard gas left behind by the Japanese. When the crew accidentally ruptured one of the barrels, the crew got burned by the gas. If the story ended there, that would be fine as the Japanese did attack China and did leave behind their chemical weapons, and did perform atrocities, etc. However, the story continues about how the construction company then sells the barrels to a recycling company and did not tell them it was mustard gas. The daughter of the recycling company gets disfigured by the gas and when the mother is interviewed, all the mother says is how she blames the damn Japanese. Never mind the fact that your own countrymen were so unscrupulous as to sell you toxic waste and not tell you about it. Now that would be even bad enough, but the story goes further and mentions how the company also sold the sand around the barrels that was used to build a children's playground and of course the kids got burned too. The moral of the story by the reporter was damn the Japanese. Never mind that our own people are so self fish that they stab their fellow countryman in the back.
4) When I was in college taking a Chinese poli-sci course the professor poised a questions whether it was in the United States interest to allow countries such as China to develop nuclear weapons and other advanced weapons. As a Chinese American, I have pride in my mother country but as the question stated, I felt that in the interest of the United States the less countries that had nukes the better it was for the US. We discussed this in groups and one group was made up of a bunch of mainland Chinese exchange students. The first thing out of his mouth was how arrogant it was that the US felt that countries such as China should not develop nukes. And then went on a tirade about how racist the US is in trying to deny others such capabilities. I remarked that this is not a matter of race, but a matter of national interests. I posed a question that if the situation was reverse, that China was the sole super power and had a monopoly on these weapons, wouldn't china try to prevent others from developing it. He wouldn't answer the question and thus I rested my case.
5) My friend who taught in China mentioned that he once asked the question of his class that if they only had 1 day to live, what would they do. He got the usual responses of visiting friends and family, indulging, etc. But there was this one girl, who was always super quiet and looked very unassuming, she said that she would buy a plane ticket to Japan and assassinate the Japanese prime minister. Again, this visceral hatred of Japan amongst the Chinese. While I do believe Japan deserves to be hated and part of that hate is Japanese government lack of apology for its wrongdoing (unlike Germany's), I find it amazing how deeply ingrained this hatred can be.
Anyway, while these stories are obviously not totally reflective of the Chinese people, I do feel they show a glimpse of some of what we're dealing with.