Being unable to perform an action is not a solution to prompt injection. A solution to prompt injection is being able to tell apart what is the real input and what is injected. I expect it to follow whatever I typed into it, and not blindly follow what it read from a file or an external source.
If they are not confident in their ability to do so, at least allow to remove the training wheels so people who know what they are doing and the risks are not patronized by the model. But you don't even get a confirmation box to perform that action, it flat out refuses.
It really is like people defending Apple not allowing side loading because you as a user can't be trusted.