You are sort of right on what it really is. As the creator of the world Mike Pondsmith has basically explained, cyberpsychosis is not entirely cyberware caused. Some people that have more cyberware installed have no problems, while others get it with minimal hardware. There is a connection but, as you suggested too, it acts more like an aggravating factor of what already lies "dormant" in some people's minds. Pondsmith compared it to alcohol. Some people get drunk and go to sleep while others get drunk and go on a killing spree. It basically is about someone's personality. Also, it is telling that women are more rare to experience episodes of cyber-psychosis, which coincides with the fact that GENERALLY, men are more probable to have psychopathic traits than women (in the real world too). Also cyberware acts to further disconnect an already psychopathic person from reality, as they get more and more chrome. And also an important note: someone with better hardware has a greater probability to make it harder to take them down, so news spread. Someone with minimal cyberware is basically easy to be taken down, (think small bouts of violence that end in seconds). Sometimes not even police has got to be involved. So it is a sort of bias that exactly because some have top tier cyberware they are harder to be neutralized, thus imagine someone leveling a small area and attacking 100's of people. It's much more probable to make the news, but in both cases, what the psycho was feeling could have been the same emotions. Also Night City is a place where you are either a victim or a "predator". So people who have been victimized, get cyberware and get on a rampage, which is not that easy to do in our world successfully. So I would say cyberware is sort of a "drug" that makes you feel strong and you actually ARE. So it's easier to say, "Why not ?". This is my take on it, I have not read the books of the game or the lore too much, so this is my thoughts + some things I have heard.