They cant. Why? Because the smartest bear ia smarter than the dumbest human.
So, these AIs are suppose to interface with humans and use nondeterminant language.
That vector will always be exploitable, unless youre talking about AI that no han controls.
The non-deterministic nature of an LLM can also be used to catch a lot of attacks. I often use LLM’s to look through code, libraries etc for security issues, vulnerabilities and other issues as a second pair of eyes.
With that said, I agree with you. Anything can be exploited and LLM’s are no exception.
Sure this is the same as positing P/=NP but the confidence that a language model will somehow become a secure determinative system fundamentally lacks language comprehension skills.