The USA are one of the biggest b#tchers in the world!
What do you expect China to say when this sale is announced.
The PRC government has an absolute line in the sand on Taiwan and this is to them a poke in the eye.
To the USA it is business for their military supplier industry as noted above.
It is also based on their congressional support of Taiwan which has been in place for many years.
If this was China selling weapons to Mexico or Cuba do you think the Americans would not be decrying actions like that?
As to the comments about allowing China to become this big so fast these statements are ludicrous. The USA wanted cheap goods and their companies like WalMart drove down the prices and their manufacturers went offshore to China and other low cost nations and this is the result.
Obama if he can do it is right to provide tax incentives to produce more at home but no one 'allowed China to grow' the same as no one can stop them from growing and becoming an economic power. At the same time as these nations grow like China, they build up their military.
The good news is that the have nations have never gone to war against other since the end of World War 2. The haves have fought the have nots and mostly the have nots each other proving that Bob Dylan got it right when he sang something like 'when you ain't got nothing, you got nothing to lose.'
The irony here is that if Taiwan ever decided to form a SAR type relationship with China formally, these weapons and planes would become part of overall China's defense system kind of like the US aiding the Afghan rebels fighting the USSR where now the US is fighting them.