The Communist Party of China operates one of the most immoral regimes in history. For instance, it kills in great numbers.
The Genocide Convention, in Article I, requires signatories, such as the United States, "to prevent and to punish" acts of genocide.
Preventing and punishing does not include strengthening the despicable ruling group by, for instance, buying Chinese products.
If there is now no reasonable hope for a benign Chinese communism — almost all observers and political leaders once thought the system would evolve in a welcomed direction — then we must not tolerate the regime, which means we have, in the first instance, a moral imperative to cut ties with it.
Cutting ties would result in ending the reign of the Communist Party, which has always been dependent on continual infusions of foreign cash.