HF need not be party to it at all, beyond being the victim. I suspect the hack is real; I have observed GLM 5.2 being able to discover similar vulnerabilities in web applications I'm hosting (which I've then fixed!). At the same time, it seems very neatly timed at an inflection point in the conversation around open models, and there's questions around the incompetent isolation under which the hacking benchmark appears to have been run.
Remember that there is generational wealth on the line for most OpenAI employees, and consider what people might do to obtain it.