It's shocking that people are this dumb, but sometimes brains just misfire in stressful interviews. Happens with the interviewer sometimes too. I was once asked, when an interviewer noticed my wedding ring, if I planned to have any kids soon and what my wife's career was, which is a definite no-no. I assumed he was joking, but he was honestly asking the question. The other interviewer stopped the interview and basically kicked him out of the room.