Thank you, Edward Snowden.

The U.S. NSA whistle blower, Ed Snowden has now confirmed that for years and years, the US has been hacking into China computers. This activity was a U.S. state secret. Now, poor Snowden has committed a crime by pulling down the U.S. pants and exposing its bum on this matter. This, is in U.S. law - A CRIME!
When the U.S. were apparently recently startled to discover that China was doing its tit, finally, for the U.S. tat, the U.S. promptly screamed, ranted and raved - to the world, that China was engaged in:

CYBER ATTACKING its computers.

It is only when a people has a civilization of thousands of years that it has the finesse of culture and good manners to behave properly.
So, when the U.S. ranted and raved at China for its 'CYBER ATTACKS', the world noted the prescient and polite silence of the Chinese authorities.
And when Obama was to meet Xi Jinping at Walter Annenberg's Rancho Mirage and the U.S. media was hammering and beating its tom-toms that Obama was to take up with China its CYBER ATTACKS on U.S. computers, China in a very cultured continued its prescient and polite silence.
Now that Ed Snowden has pulled the U.S. pants down to expose its years and years of the Amercan bum on top of China's computers, in a cultured way China as retained its prescient and polite silence.

Silence is golden.

Silence is cultured and good mannered.