Can you elaborate on this? On the face of your comment, I think you might just be unaware of a lot of films that have been made in the US. The article mentioned the American David Lynch's Eraserhead as an influence of these works. David Cronenberg is also undoubtedly a huge influence here as well (I know he's Canadian, but he largely works in the American movie industry).

It's not like Tetsuo: The Iron Man was a huge financial or mainstream success. Most of these movies were mostly relegated to the grindhouse, and American has more than its share of grindhouse film makers (ala John Waters). Also consider that The Fly was as big a financial success as Akira.

Basically, what I'm saying is that I don't think Japanese artists & audiences are very different from their American counterparts in this regard. It is not distinctly Japanese or American to dream up horrific stuff, but rather, it's human to hold up a mirror to an, at times, horrific existence.