Essentially the US spent all that effort trying to prevent others joining the AIIB and failed. But they really won. You see China getting more countries to join is a step backwards. This type of propaganda will make Goebbels proud.
This attempt at comedy courtesy of the New York Times and I will just post the relevant bits.
http://www.nytimes.com/2015/04/06/opini ... rd=A5&_r=0
In fact, the United States government has nothing to fear from the A.I.I.B.; its opposition is misguided. The bank’s creation will not enhance China’s global power at the expense of the United States. If anything, Beijing’s attempt to go multilateral is a step backward: It’s a concession that China’s established practice of promoting bilateral initiatives in the developing world has backfired.