It's a valid point when applied to a lot of other situations. For example, the world expected us to help out with the tsunami victims a few years back, and the current tsunami situation in Japan is similar.
A lot of the most vocal Americans can be characterized that way, but I would say that there is a growing interest in isolationism here right now. We've learned a hard lesson from Iraq and Afghanistan, and so a lot of us are reluctant to support more interventionism.
I can't speak for him, but personally, history suggests that, as China grows more prosperous, they will intervene in more conflicts. They've already done this some in Africa -- in Sudan in particular. China already plays the economic imperialism game quite well by investing heavily in a lot of power players like the U.S., Australia, Brazil, and various parts of Africa. This is usually the first step towards more military interventionism, since economic investments abroad can lead to vested interests in conflicts that might affect them.