The thing to remember here is that this is not 1 person out of 10k, it is someone this company/team has specifically selected to perform the role of both interviewing you and trying to maintain your interest in the company and role. If a hiring manager is so bad that they would put someone like the person who OP encountered into a hiring loop then it is a good indicator that either the company is poorly managed or that the people who were not involved in the interview loop are even worse.