So not sure what this designer is describing but it is not human-centered design. In fact, it’s the exact OPPOSITE of human-centered design. By definition, designers are ill-equipped to design anything but for themselves if they do not understand the behavior, motivations and decision-making actions, among other traits of the people for which they are designing. This eliminates the designer from the user pool. The human at the center of human-centered design is, by practice, decidedly NOT the designer.