Yes, America has enjoyed its massive worldwide influence over the past few decades and it has definitely gotten away with abusing it's power at times. Much of it was because the flow of information wasn't as free back than as it is today, but it was also because America, for all its faults, really did at least try and do a lot of good as a "self-appointed world leader".
My opinions aren't exactly unbiased having grown up in South Korea (recipient of lots of good will from the US), but the situation isn't simply that America has lost its edge over China and is complaining - it's more that Chinese government is really aggressive in promoting their agenda and are much more willing to sacrifice certain ideals (freedom of expression, etc) to get there. I can say this as a person who have attended a secret Christian worship meeting in China: Say what you will about the US, but it's not China.