This is true.

I've lived in a couple of countries and an interesting thing I found out is just how attuned we are for the country we grew up in to certain markers (accent, clothing, the kind of words people use, etc) of Education, Social Status, City/Countryside origin and so on, but not at all for other countries since most of these things tend to be different from country to country and it takes some time living elsewhere to start reading such things on the locals, and even longer before it becomes instinctive.

(Mind you my experience was just Europe, which can hardly be said to have a vast cultural distance between countries - I mean, it's varied but it doesn't have, say, Japan-to-India levels of contrast - and yet all 3 of the countries I live in for years - Portugal, The Netherlands and Britain - in general have significantly different cultures and vastly different markers for such things)

So it's funny how this specific item has become an amazing signal for people abroad of Uncut Low Education status for Americans.