This simply isn't true. I live in Thailand. Most locals here don't have access to US stocks, or don't know that they do. Young people here have a Thai stock trading app (for the SET, which is the exchange) on their phone and another one for their domestic cryptocurrency exchange of choice. I think very few of them are buying AMZN or TSLA.
I'd bet fewer than 3% of the population here are buying US stocks.
I'd bet fewer than 3% of the population here are buying US stocks.