It's quite a common pattern these days: I often see candidates who choose a language because they think it's better suited for interviews, not because they know it well (we leave the choice of programming language to the candidate).
Sometimes this works well, sometimes it really backfires on them. Coding is one of key rubrics on which we assess software engineering candidates, and if the only signal I have is that they don't know know their chosen language very well, it's hard to justify scoring that rubric highly.
The root comment is saying the interviewee knows the language well enough to consider one solution better than another solution.
And this was misinterpreted by the interviewer as not knowing the language.
An effective interviewer would have asked "Why are you doing it this way?" instead of assuming - wrongly - it was all the candidate knew.
This actually matters. Before you even get to coding skill you want people who can parse reality accurately, and not make incorrect assumptions about what's happening in front of them - either out of narcissism and arrogance, or because of poor communication skills, or because they're following a set process which is bureaucratic and inflexible and operates with a poor signal to noise ratio. (Among other possible reasons.)
I really well versed with Python, Golang & Rust. I will not choose Rust for interviews. For me, Python is much more productive in an interview setting.
I didn't mean to imply that this applied to your case. Just a general observation (rather frustrating for someone like me, who wants candidates to do well but not that infrequently sees them being let down by their own choices).
