That statement ignores a big part of the black metal aesthetic and does a huge disservice to the many great musicians in the scene. The raw production values were in response to the rising popularity and commercialization of death metal around the late '80s and early '90s and the 'plastic' production that came with it. Listen to Soulside Journey and then A Blaze in the Northern Sky and try telling me it wasn't absolutely intentional. Then listen to anything Emperor released and try telling me "they lacked the musical ability to rival the predominantly (at the time) Swedish and American Death Metal scenes."
Euronymous spent tons of time perfecting the production of De Mysteriis Dom Sathanas. Whether it sounds harsh to the average listener or not (it does), he went out of his way to have 1) audible bass (check it out on headphones sometime), 2) thunderously huge drums and 3) cacophonous guitars, true to his playing style. These were all calculated, intentional decisions, meant to drive the cold, bleak aesthetic.