Nobody cares, as in nobody cares about using it, much less legalizing it.

Most Japanese people who’ve tried it did it once while traveling to Canada or America.

Why should it be illegal in the first place then if no one cares about it?

Because America wrote up the framework for post WW2 Japan, and drug laws are a part of that.

Nobody cares to repeal the laws because nobody is sticking their neck out to call for legalization because pretty much nobody is seriously using them. There aren't tens of thousands overdosing and dying on opiates and there's no debate on how high is too high to drive. It's simply not a concern.

Ah interesting. Makes sense.