The infamous 'anti-pornography laws' actually predate Perry by a significant period of time. Those were a Tokugawa era law originally. Post WWII occupation has had very little actual impact on Japanese culture, no matter how impactful the occupiers think they were.

It's the first time I've seen this put forward, I thought the effects of occupation were obvious and undeniable. To me at least there is a clear influence in art/music/cinema, technology, and food. Though over time, it fuses to the point of being its own thing.