Earlier quoted context omitted.
As an interviewer, how do I know that you wrote that code in your GitHub profile?
Code often doesn't stand alone, there's going to be a commit history, there's often going to be comments and issues on other projects. Ask questions about the code: - why did you write this in this way - explain how this works - if you needed to add X into this, how would you do it - are there other ways to achieve what you did here, what are the pros/cons of this? - what would you do differently if you were to re-wr…
It was very obviously there as bait for people like you and it was removed as soon as they took a new job. It was never used in production in its "released" form.
I had no problem with the person's abilities to code, but for reasons like this I probably wouldn't work with them again, or hire them as a eng lead or higher.