dont think our government doesnt do the same thing. i believe with my entire being that our country hides and changes history as much (if not more) than any other counrty out there. no one can change my mind so dont bother trying.
History is usually written by the status quo of the time, so in that sense, I have no doubt that our own history is colored to favor the perspective of those writing it. However, with the inherent competition of ideas and the (more or less) free press, it is actually very hard to majorly cover up significant events in our country. If something significant happens, you better believe someone will document it some how, and our government is severely restricted when it comes to suppressing an individuals speech.
Just go read my blog on myspace... If I said similar things in China, you probably wouldn't ever see me again. They're main stream media is exclusively created by the government.
We know about the LA riots, project MK-ULTRA, Hiroshima & Nagasaki, the two million defenseless Korean villagers we bombed, the Japanese we put in concentration camps, the civil rights movement, the Vietnam war protests and riots, the Stonewall riots, the Downing Street memo proving Bush was trying to find a reason to go to war with Iraq before 9/11, we even know about our current government using torture, building secret prisons abroad and concentration camps right here, right now... nearly all the dirt you want on our government is available with a bit of research.
This is not the case in Communist China. Their government has far more power over their citizens than the U.S. ever has...