I'm glad that the US has suddenly started caring about labor rights and the well-being of Muslims, and I'm sure that it's just pure coincidence that it happens to be aligned with criticizing and fear-mongering it's largest competitor.
There are plenty of poor countries with worse conditions than China. Major multinational corporations set up shell corporations to run their sweatshops and if they get exposed they say, "We had no idea," maybe pay a tiny fine, then set up another company to do the exact same thing. Many of these countries are in the US's sphere of influence, and many have to sign away control of their own domestic policies as a condition for entry into the global marketplace, while their resources, stolen by force by colonizers, remain in foreign hands.
Why isn't the US concerned about their labor conditions? I'll tell you why: because one of those cases means giving more money to rich corporations in the form of defense contracts, and the other means restricting the ability of rich corporations to exploit the poor. All the bombs the US is building will do nothing to improve the conditions of anyone living in China, while there are plenty of people who the US could be lifting out of poverty if it cared to.
The sudden decline in relations was not because the whole US just woke up one day and decided to start caring about the conditions of laborers in China, which used to be much worse than today. Don't feed me that nonsense.