I haven't taken a plane in over a decade, so this system is news to me. Apparently the scanner looks for deviations from from what a normal human body without objects under the clothes would look like. Since men and women have different body shapes there's a scanner type for men and another for women.

This tranny got a boob job, so going through the male scanner detects abnormalities in the chest area and the female scanner defects abnormalities in crotch area when he passes through, because women don't have dicks and men don't have tits, despite what the degenerates want you to think. And somehow the agents are transphobes, because of course. As if the agents designed the scanners. She even asked him if he wanted a man or woman to pat him down, but that was somehow a faux pas as well. It's almost like there's no pleasing this freak.