If the average is "5'9"", it's not logical for it to be even jokingly called short and by proxy 5'8" as well, but it's really common - there's no way it would be the case if the average truly was 5ft 9 and by proxy 5ft 8 would be averag
The population for comparison is young people in first world countries, and sure enough, looking at the averages for young people it looks like about 5'10.5" / 179 cm in western countries, which makes a lot more sense and explains these 5'9" - 5'10" guys on boards like reddit on r/short, even accounted for heightfrauding.
https://en.m.wikipedia.org/wiki/Average_human_height_by_country – what are your thoughts on these figures, specifically the 19 year old averages and the urban figures in Asian countries?
Listed some here.
United States: 5'9.5" / 177 cm
United Kingdom: 5'10" / 178 cm
France: 5'10.5" / 179 cm
Germany: 5'11" / 180 cm
Australia: 5'10.5" / 179 cm
Canada: 5'10.5" / 179 cm (not sure about this one..)
Spain: 5'9.5" / 176 cm
Italy: 5'8.5" / 174 cm
South Korea: 5'9" / 176 cm
India: 5'8.5" / 174 cm
Turkey: 5'9.5" / 176 cm
China - Beijing: 5'9.5" / 177 cm
Philippines: 5'5" / 165 cm
Japan: 5'8" / 172 cm
Hong Kong: 5'9" / 175 cm
United Arab Emirates: 5'8.5" / 174 cm
Overall I'd say 5'9" to be average in Asia, 5'10.5" in western countries.
The average for Hollywood actors seems to be 5'10.5-5'11" according to the celebheights.com database.
Feel free to let me know your thoughts and whether you agree or disagree.