The eventuality of any income obtained by Americans is that it ends up becoming disposable income.
After paying for necessities such as rent, mortgage, food, car payments and insurance, and maybe some for savings, a significant portion of what is left goes to China.
In the past 40 years, the U.S. economy has transitioned from manufacturing to predominately a service and consumer-based economy. To put it simply, the U.S. does not produce many of the consumer goods that Americans are buying.
Being a consumer economy, the Americans need to consume. When U.S. stimulus checks and Paycheck Protection Program loans hit bank accounts this and last year, they unintentionally stimulated the Chinese economy on an unprecedented level.