Having the red line as genocide, or as slavery from the buying and selling of people feels like a pretty safe line to have. Blocking goods is a very serious move in international relations.
The US justice system is not inherently racist, it's systematically racist, which isn't good, but is a different thing. Nearly every person in the US prison system is there because they committed a crime. The people in Xinjiang did nothing but have the wrong culture and skin color. It's still a false equivalency.
Anyone can involve themselves and investigate the US court system, they can file complaints, they can sue for unfair treatment etc. International monitors are barred from Xinjiang.