Don't be so sure they don't have the capabilities or motivation for that matter. https://www.tamus.edu/systemwide/05/09/research/china.html
"Governments have also used extra males in the development of unexplored territories and encouraged them to migrate to other countries. To more extreme ends, some governments facing similar dilemmas have ignored in-group violence and even encouraged divisions among excess males, leading to increased violence and self-destruction, he explains.
Even more disturbing, China might be tempted to send its excess manpower to invade another country, possibly Taiwan, Poston says, noting that Portugal sent its extra males off to wars in North Africa. China, he says, is already co-opting young and poor unmarried males into the People's Liberation Army and into the paramilitary People's Armed Police. In the next few decades there will be many millions more such males available for these kinds of activities, he adds."
The Chinese don't need that carrier they are building, or all those J-10s. They'll be able to build a bridge of people to Taiwan. Overpopulation could be impetus enough for China to become quite the conflagration - throw in the global economic collapse (which, mind you is reported as being even worse overseas than it has been here) and you have a region ripe for war of one kind of another.
Before WWII started, millions of people across the globe thought that worldwide conflict would be impossible - we were too closely tied economically and weapons of war had become far too powerful to actually use. Ironically, this was the same attitude that permeated societies before WWI, the Russo-Japanese war, the Austria-Prussian War of the 1870s and even our own Revolution. I am not saying that battle with China or any struggling nation is inevitable, but given the challenges that our and other nations face, and the naturally emotional and irrational behavior of large groups of troubled people, it is certainly overwhelmingly arrogant of us to dismiss the idea as preposterous. Now more than ever, we should be extremely wary of our ability to defend ourselves and our assets.
Remember, that no matter how "interdependent" the talking craniums on TV say the global community is, when push comes to shove, the big dog has to eat. In time, the only question may be, who is the biggest dog on the block? And I sure as hell hope he's on my side.