the position was for a front-end role, but the company itself is more "low level" than that.
it was just one of those situations where the vpe is a very smart person, but has no clue about the front-end, and apparently this was a pet question of the vpe. i don't think i "lucked out" since the people i would have actually had day-to-day interactions with were fine people. but yeah that is definitely a blind-spot for them.
You lucked out then, I think. If they were looking for a front end developer and asking questions about semaphores, something is definitely wrong.