I think you are ignoring environmental factors, which explain the differences
in philosophy you site.  Specifically, what happens when a treatment has
been known for 20 years, and has never been proven effective?  Technically,
this treatment is "unproven", but from a practical point of view it is
"disproven".

Philosophers (who are not faced with life and death questions) can afford
to take a theoretical outlook.  Doctors (who must treat real diseases in
real people) take a practical view: if a treatment has not been proven
effective in a reasonable amount of time, then it is not effective.  It
has been disproven.