It's true that some Chinese products are bad. Some American products are bad, too. However, if someone says that all Chinese products are bad, that is clearly prejudice and insult.
The problem is that in verbal conversation, it is often not clear he means "some" or "all". Listeners also have different sensitivity and may interpret statements differently. So when you feel uncomfortable, you can ask him to clarify exactly what he means.
"Do you mean you buy ONE bad product from China? I bought several bad products made in USA, too."
If he takes the position that all products made in China are bad, then you have a case against him. The HR term is called "hostile environment". I'll first let him know that his statement is not true, makes me feel uncomfortable and creates an hostile environment. Document your case and discuss with HR.
