Exactly. There was some fuss a while back about a similar classifier for sexuality. It turned out to be guessing mostly based on head tilt, personal hygiene and whether the person was wearing glasses. The physiognomy component was ~nonexistent even though it was publicized as though it weren’t. People intentionally if at times subconsciously present themselves in a way that signals information to kindred spirits. You’d need to bring in hundreds of people, wash them and basically take mugshots to control for that.