Once upon a time when a person contracted an incurable disease, for safety reasons and for the benefit of other community members, that person must be declared unclean. That means the person is being cut off from the faith community. He is not allowed to worship in the temple and has no right to dispute. He is being treated as harsh as a criminal with strict laws enforced to make sure that the rest of the community is safe from that kind of disease. After being cured that person must be examined by the community leaders before accepting him back to the community.
Being cut off from the faith community means that person is not in communion with the community and receives no benefits from the faith community. This form of corporal punishment is long dead because it is inhuman and contradicts to the teaching of Jesus, whose teaching is based on love, forgiveness and respect. Choosing not to belong to the faith community is an option for many in the modern world; while in the pass it was a form of punishment. Both approaches are two extreme and both arrive from human reasoning. Reasonable and logical arguments can't guarantee that it is always correct and right especially when it talks about the spiritual world.
People who choose to live a life that has nothing to do with the spiritual world because they deny the eternal life after death. They believe in the physical and psychological world and these are important for the well being of their physical body. We spend so much time, energy to take care of our physical body and then simply bury it on earth. It must be a great waste if there is nothing after death.
We Christians believe that physicians can cure our physical sickness but not heal our spirit because it is beyond their capacity.
People who put their faith in the physical world for healing run out of option when the experts told them we are sorry. Christians enjoy receiving treatment from both the experts and God when the experts told them they have run out of options we turn to God for spiritual nourishment and we never run out of hope.