In “tell me about a time...” questions, the interviewer has some idea of how he would expect his coworker or report to handle such a situation. That idea is culture. The candidate’s response doesn’t have to be “toxic asshole” to be very different, and therefore a culture fit concern.

I have seen candidates rejected for telling stories where they were too cooperative with coworkers they knew to be wrong. Some interviewers in technical rounds will second guess the candidate on correct decisions to see if they stand their ground.