In your scenario, did the script kiddie get control of Microsoft's Bing? Or are you describing a scenario where the script kiddie spins up a knockoff Bing (either hosting the GPT3 model or paying some service hosting the model), advertises their knockoff Bing so that people go use it, those people get into arguments with the knockoff Bing, and the script kiddie also integrated their system with functionality to autonomously hack the people who got into arguments with their knockoff Bing?

Am I understanding your premise correctly?