There are also plenty of non-country entities that have flags. I live in Buffalo, New York, USA. There's a flag for the USA, a flag for the state of New York, a

There are also plenty of non-country entities that have flags. I live in Buffalo, New York, USA. There's a flag for the USA, a flag for the state of New York, and even the city has its own flag[1]. So even if we accept that Taiwan isn't a country there's no reason an island can't have a flag! [1] https://en.wikipedia.org/wiki/Flag_of_Buffalo,_New_York https://en.wikipedia.org/wiki/Flag_of_Buffalo,_New_York