I don't understand the point you're trying to make. Is it culturalism to say that Western cultures value free speech? If you just wanted to say that parent was wrong that Chinese don't value free speech, why the diatribe about culturalism and racism?
You also haven't really put forward any argument that the Chinese value free speech - you can make a base argument that it's valued in some Western countries because they've codified it in their laws - most notably the FA in the US(it's questionable how much this "basic right" is respected in reality). Calling it a "basic right" is culturalism by your own definition, as you apply your own cultural values(whatever they may be) over the whole of humanity. What makes you think humanity as a whole values this "basic right"? Millions of people live in countries where free speech is not as important as religion, for example, and blasphemy laws exist.
You seem to omit that's possible that we have universal pricinciples that's superior to whatever culture. You can attain these principles via philosophy. Any individuals can rediscover the values of free speech, freedom of government arbitrary, freedoms of thoughts and actions by just reflexion itself.
One cannot disassociate philosophical principles with the culture and history that brought about it.
By claiming there's some Universal Principal that's superior is basically saying that you're own beliefs and culture (presumably the one and the same as the proported Universal Principle) is superior.
This isn't mathematics where there's some objective truth.
You also haven't really put forward any argument that the Chinese value free speech - you can make a base argument that it's valued in some Western countries because they've codified it in their laws - most notably the FA in the US(it's questionable how much this "basic right" is respected in reality). Calling it a "basic right" is culturalism by your own definition, as you apply your own cultural values(whatever they may be) over the whole of humanity. What makes you think humanity as a whole values this "basic right"? Millions of people live in countries where free speech is not as important as religion, for example, and blasphemy laws exist.