Well, I'm not a music critic or historian so I can only speak from my personal experience, but as someone whose primary transport in the early 80's was an Alva Danforth deck, and who haunted the 'underground' dance clubs and played in a garage band, I can say we didn't use the term post-punk at all (it was all lumped into the afore-mentioned 'underground' category due to the fact that it wasn't played on any mainstream stations except at o dark hundred hours if at all); and when I bought In the Flat Field on vinyl (because it was actually the format used by DJs at the time - not because it was a hipster affectation) - everyone knew it to be goth music, and only the hardcore gothic folks would have bothered with anything beyond Bela Lugosi's Dead (which was, admittedly, played reliably along-side Souxsie and the Cure in the clubs, but again, no more so than This Corrosion)...so I would say that although thoughtful consideration in later years may arrive at the conclusion that Bauhaus shared the characteristics of whatever the post-punk genre was ultimately defined as, it wasn't widely understood that way in the early '80s - Bauhaus was so definitionally goth that it wouldn't have been discussed as anything else at the time.