Not necessarily. You don't know why they're making that claim.
I live in Korea, where the letter of the labor laws are quite strong. However, they're not enforced. Workers don't sue companies because they're either afraid to rock the boat due to cultural norms or afraid they will develop a reputation and become unhirable.
Korea and China are very distinct cultures, but there are key facets that are common between them. Confucian (or at least neo-Confucian in Korea) values prioritize maintaining the peace and deferring to authority. This is one of several factors that causes Koreans to endure intense working hours, and I'm more willing to believe Chinese folks overwork a lot due to the few shared values.
Aren't most states ethnically associated...? Like... the US and Canada are anomalous. European countries are particularly accepting of other ethnicities but still have a core ethnicity. Asian countries are usually pretty homogenous. I imagine African countries are, too. Latin America, I'm not as sure.
Or am I misunderstanding the definition of ethno-state?