the reason to pick Chinese may be racist (possibly due to the writing system looking complicated) but the thought experiment itself doesn't have racist connotations imo, and i don't think it's stupid either. doesn't have to involve Chinese or a specific language at all.
it's a logical question to ask: if i can mimic speaking in a language to a point that it convinces native speakers, but don't understand what I'm saying myself, am I considered a genuine speaker of that language? does what i say matter or have any value?