There are valid reasons why adults wear diapers.

anything ranging from disabilities, incontinence. Even new moms experience needing diapers. Learn more about the world before assuming no one is " gross enough to think that". The person that made that comment sounded like they have no real world experience. They probably also never had to experience the bathroom woes of public transportation. Like having a full bladder when the bus driver goes over a pothole that the city refuses to fix