Unclean here—eating with unclean hands—is not a question of hygiene. This is ceremonial purity: being right with God or being pure in your body when you do certain acts. Another thing that’s important in the OT background is that not only is this not about hygiene, but these are not actually OT commands that the Pharisees are referring to. In the OT, everyone is not commanded to ritually wash their hands before eating. There are certain washing rituals related to the priests, but those aren’t applied