Well, the fact that they even had the head of QA/testing interviewing for a product manager role is curious.

My assessment is that it was a trick question. If the company previously had issues with loosely identifying Product Management roles, it’s possible the technology side had a bad experience with a Product Manager stepping out of bounds in determining and forcing a particular stack. Engineering would be unlikely to appreciate this.

Overall the interviewer didn’t sound like a great person, and he probably was looking for you to say that it wasn’t up for you to determine.