I don't have a lot of sympathy for China

China owns $1.3 trln in US Treasuries.

Does it own them because it thinks the US is a worthy investment?

No. It owns them because in the process of managing its currency to maintain export competitiveness it has been forced to buy huge amounts of US assets. Most of those assets are warehoused in highly liquid US Treasuries. The purchases are made out of Chinese self-interest, nothing more.

Moral of the story: If you don't want to risk a hangover, don't go on a binge. And if you do go on a binge, don't cry to the brewery. You only have yourself to blame.