The comment to which you refer comes from an unknown US Intelligence source; You can always find anonymous intelligence sources to say just about anything.
Ahhhhhhhhh...It's prudent to take in all scenarios.
China has been building up its military and ability to project force, why? It's under no direct threat from any of it's bordering nations...though N.K. is a plausible threat, it's remote at best. Besides, China doesn't need to build up a large ocean going navy to take N. Korea...and they have been building up.
So what is the REAL THREAT? Seems like CHINA views the U.S. as the largest threat to the continuation of it's Moaist State...that an perhaps some pressure from within.
They want TAIWAN because it's a national symbol of "UP YOURS!" to the Moaist Regime and adds fuel to the fire for potential, and natural, regime change in China...if they crush TAIWAN...they quell, perhaps, future threats from within.
Well, if they attack TAIWAN...we'll probably defend the island with carrier battle groups...etc...CHINA, at least for now, has little answer for such force with conventional detterrents...more likely they would use low yield tac nukes to destroy a battle group at sea, but maybe not...but it's plausible. Are response would be to nuke mainland China military command and control centers as well as other strategic locations...lots of Chinese in those areas...they'll need the shelters.
Perhaps China is simply quelling unrest from the "HEAT", maybe? But there is no reason not to believe there is a dual purpose in the actions of the Chicomms.
IMHO you play out all scenarios, and dismiss nothing when it comes to the Chinese.