One washes and otherwise prepares food in the kitchen sink, frequently laying it during some part of the process on the surface of the sink. Detergent residue doesn't make food tastier, nor do hair (especially pubic hair, yum), bleach, detached lint or threads, body oil or other physical debris or bodily offputtings which I leave to the imagination, etc. etc. add to gastronomic desirability. One should leave the kitchen sink in a state appropriate for its characteristic usage.