The issue has never been previous status as colony but society and culture (East Asian countries and Sinpgapore are all part of the sinosphere culturally).

I don't think that's entirely true. Britain forced colonies to export only when beneficial to the domestic British market and forced them to import to benefit the domestic British market: India may have produced cotton, but under colonialism it had to import cotton goods from the UK.

Japan did not view Korea as a place to enrich for anyone's benefit but Japan. The same with their occupation of Taiwan.