Because in the ancient world, someone who had leprosy was perceived not only to have a physical ailment but also a spiritual ailment.

If the reason isn't down to a physical ailment, then a refusal of a drink can become synonymous with a rejection of friendship.

Perhaps it was a physical ailment.

Those receiving treatment have found themselves without the choices and care that they might expect if they had a physical ailment.

But it was actually a physical ailment thing.