You are strawmanning.

There is an internationally accepted and recognized scale for English language ability. Where you fall on this scale can be tested. The result you get aligns your English ability against the international standard. Employers and universities use this in order to ascertain the fluency level of a candidate.

You can continue your strawman posts. It doesn't change the fact that there is an ability scale, you can test for position on that scale and it is internationally recognised by education establishments the world over.

Like so many on here, you fail to look at the ESL world as a whole and focus simply on China. IELTS and CESOL are international exams, thus meaning a candidate from China will be assessed on the same scale as a student from anywhere else in the world, ergo international standard of language ability.