You're an aficionado of the "borrowed knife" theory, under which, net-net, every nuclear weapon in the (third) world will be more of a problem for the U.S. than for China.
But why would China want Iran to have the Bomb? After all, China's no more Moslem than the U.S., or barely so. Why would an "Islamic Bomb" be of benefit to China?
Islam destroys us, then China overwhelms Islam and destroys it, then claims control of the world...like a vast game of Soduku.
How do end a game of Soduku when one is losing?...one overturns the game board!