It's overwhelmingly brought up when talking about Japan (and sometimes Korea) in comparison to the US (or EU). With Japan (or Korea) being the high-trust culture in that comparison, and the US/EU being the low-trust one.
I guarantee you can do a search across mentions of high/low-trust culture across online platforms in the last 12 months and the large majority will be these contexts, i.e. Western countries described low-trust, not high-trust.
I wouldn't necessarily call it a "racist dog whistle" myself, though - there is a very real pattern that's being pointed out but the reason I made the GP comment is that from my experience I would assume that Chinese culture is about as trustworthy as the West.
Agreed, get off X anyway.
> This isn't true at all in general online discourse.
Maybe, but is this relevant? Was the grandparent comment "general online discourse" or was it specific online discourse coming from a place that does in fact use such language in that way.
With your logic, every fact you dislike that makes your side of the argument look bad, can be dogwhitlse.