I discussed it briefly. My interviewer was unpersuaded, and the other interviewer in the room (who wasn't performing this interview) suggested we just move on. I believe the unconvinced interviewer was simply a very junior developer and an even more junior interviewer. He seemed quite nervous.
One of the worst interviews I've had the interviewer was not only similarly incorrect, but then afterwards proceeded to try to give me advice on interviewing skills, and how I should've "taken his hint" and been "more amenable to other answers". I probably would've been open to alternate answers if they were, y'know, factually correct.
1) Interviewer insists that an operation must be n^2 "because it has a nested loop" even though the nested loops are only iterating over their own subset of the master string.
2) Interviewer refuses literally any test that would help decide which of us is right.
3) Interviewer turns out to not even understand the concept of resolving disagreements by appealing to agreed-upon facts, insisting that he would only be convinced by the absence of a nested loop (i.e. talking about some other algorithm).
4) Interviewer is five-year backend lead.
5) Interviewer vetoes me from the rest of the process purely because of that disagreement.
6) Because I thought I was going insane, I implemented it at home and ran the problem with different sizes and the run time with up as O(n) like clockwork.