That part was not 100% serious. Only 90% or so.
To err is human, I know that as much as anybody. Before the advent of LLMs, there were several (human) audits of my code for vulnerabilities, but they found little, which I was proud of. And now, Mythos had a quick look and found hundreds and hundreds of bugs (many of which were critical and even more were really emberassing).
Of course, I knew there were bugs that just weren't found because the auditors weren't looking closely enough, didn't have enough time/budget etc., but this unspecific feeling is different from having all the bugs accumulated over a quarter century slapped in your face at once.
Code auditors are a crapshoot. I worked around financial auditors and they were much more consistent but thats likely because standards are more well defined.
If you get a good auditor they can find a ton, but most are box checkers there to make the audit company as much money as possible.