Here's the language that makes me think they are taking this seriously:
> We are sharing preliminary findings at this stage to help defenders understand what happened and to help calibrate on what models are now capable of. We will continue to conduct a thorough investigation alongside Hugging Face and will share more details on the vulnerabilities, incident, and findings when our investigation is complete.
That's not well massaged PR language - that's the kind of thing you dash out when you see a major shitstorm brewing (HF had already publicized the attack before they knew it was from OpenAI) and you want to get ahead of things while you're still pulling together the full story.
I expect we'll find out within a few days if OpenAI are going to keep their promise to "share more details on the vulnerabilities, incident, and findings". If they don't do that I'll reassess how I interpret their initial post.