You are ignoring the aesthetic and cultural overlaps between the four genres and their constant crossovers. I wont mention NuMetal, which sucks, but seek out some of the funky punk stuff that, usually, comes out of London -- you might even hear some ska nuggs in the mix :-)
This was the eighties, it was probably less obvious (and we were both probably somewhat sheltered). Suffice to say we introduced each other to a different culture, which I think was the point of the article.
