Punk
The punk subculture started around the mid 70s in the United States and United Kingdom, so when Gibson was writing in the early 80s, it was a full-blown cultural zeitgeist. As a result, a lot of punk rock inspiration was making its way into other artistic mediums like fiction (hence the punk in cyberpunk). In Neuromancer, this inspiration can be found in the tone. Check it out:
Was [the Mitsubishi-Genentech logo] authentic? If that's for real, [Case] though, he's in for trouble. If it wasn't, served him right. M-G employees above a certain level were implanted with advanced microprocessors that monitored mutagen levels in the bloodstream. Gear like that would get you rolled in Night City, rolled straight into a black clinic. (1.69)
The anti-establishment and rebellious tone of the narration here are central ideas of the punk style. In this case, power and authority of Mitsubishi-Genentech holds no sway in Night City. Case also seems to suggest that by "selling out" to M-G the man will get what he deserves. Yeah, selling out is a big no-no in the punk scene. By Night City's standards, the man not only will but should get beat up for being so stupid as to flaunt his tech. This is a very different outlook from the traditional social view of "it's not nice to beat people up." Way to stick it to the man, buddy.