stray_pengo: I know this is on the publisher, but that doesn't make it any less disappointing. It's unfortunate that even GOG couldn't persuade Konami to play fair (speaking as a native Japanese.)
TheBigCore: I can only assume Konami did this because China is the world capital of software piracy. South Korea doesn't have that reputation, so that is a bit strange.
Your assumption is illogical. Preventing someone from buying the game that person wants to play is only forces that person to find a way to play the game by other means which are often limited to piracy when it comes to digital games.
Since whole region in blocked it's very simple - another case of licensing issues. Just like Super Robot Wars situation. Rest of the world outside SEA region got only OG games just because licensing hell with music, robots etc licensed exclusively to a lot of different companies.