Have you lived in Japan? Because this is an almost stereotypical outsider view of the country. Japan has draconian drug laws, up to 10 years for minor possession. People can be held in detention, repeatedly, for weeks without being formally accused. Police is visibly present in public.

All of East Asia is homogeneous. Every country is highly paternalistic and legalistic. North Korea is probably both the most homogeneous and authoritarian country on earth.

In reality heterogeneous societies are significantly less prone to this. You could not turn India or the US into comparable police states because nobody would even agree on how to get there. Singapore gets away with it because it's effectively a small city state. A country of similar composition but 10x larger, which happens to actually exist just North, Malaysia, could never maintain that level of repression.