How long ago did this happen? The summary didn't list the date of the submission of the "testimony", but thing like this tend to take time to process, so I'm guessing that it happened well over a year ago. This make his claimed "honest mistake" due to ignorance believable. But it also negates your point.
That said, they won't be able to stop hallucinations without breaking the AI models. That's a mistake that people make all the time. What they need to do is prioritize having the AI determine how certain it's statements are, and including that in the statement...but people won't like that kind of answer.