Pure hubris. He worked on the system, people are saying that it is fatally flawed and he's just not accepting that possibility because it feels like a criticism of him.
He can't imagine the bug so the most likely explanation is theft.
We see this attitude here all the time, e.g. the people that think they never write bugs, and tools to avoid them like static typing, Rust, tests, etc. are just for lesser mortals.
My personal bit of hubris is feeling like I create interesting bugs in spite of the tools available. Lots of "compliance is not equivalence" lessons to identify and hopefully learn from, for example.
Yeah it sounds unbelievable but there really are. Maybe not many that think they never write bugs, but plenty that think they very rarely make the same mistakes that everyone else makes.
If you search for "don't write bugs" on HN there are hundreds of results where someone has effectively claimed that.
More than one of my bosses: "I don't understand why this is taking so long ... look I implemented it in 10 minutes, here: [link to commit that failed CI with syntax errors]"
Its amazing that someone could find errors they made in their code, "finish" fixing them, and then surmise there could be no further possibility of errors.
If anything this mental state is a sign of an infinitesimal amount of software experience, or maybe a well spring of infinite naivete we could mine to power space faring civilizations.
I find it most often in leads that get promoted a little too quickly and are still in the dangerous “advanced beginner” stage where they know enough to be dangerous but still lack expertise to know they have no expertise.
He can't imagine the bug so the most likely explanation is theft.
We see this attitude here all the time, e.g. the people that think they never write bugs, and tools to avoid them like static typing, Rust, tests, etc. are just for lesser mortals.