Semantics

I looked up the Merriam-Webster Online Dictionary and found the meaning of espionage:

the practice of spying or using spies to obtain information about the plans and activities especially of a foreign government or a competing company

Note that the keyword here is foreign. Hence, the premise for espionage acts carried out by one government on another is the sovereignty of both states.

How can the Taiwanese government be a "foreign" government when the mainland Chinese believe that the capital of Taiwan is not Taipei, but Beijing?

How can Taiwan be engaging agent to "spy" on China when Taiwan is, as claimed by China, an inseparable part of China? It is analogous to someone from California charged by the federal government in Washington for "spying" on the USA. I mean, this does not make any sense.

Therefore, the charges levelled at Straits Times correspondent Ching Cheong should be subversion or sedition.

By charging Ching Cheong with espionage is in fact unwittingly acknowledging that Taiwan is not a part of China.

The Chinese government had not merely slapped some charges on a journalist. They had also just slapped themselves in the face.