Xi is a megalomaniac, and following in the footsteps of his hero, Mao. Mao offed 60 million Chinese to prove a point. A few million deaths in China is a small price to pay to drag down the West and make a point.
The West (Trump) has tweeked Xi's nose. Xi's quest to elevate China to #1 world superpower, by stealing intellectual property from the West, using cheap slave labor to build ultra cheap products and run the competition out of business, and building up its military and expanding into international waters with artificial islands, has been halted. Not only was he hit by Trump's trade wars, but also by the West-inspired Democracy protests in Hong Kong.
American economy tanks, which takes down Trump, which keeps the House in Democrat hands, and China wins.