I am sure there are people who have an enhanced resistance to smallpox (though clearly no known bad side-effects).  Our response to smallpox was to eliminate the disease since not everyone would have smallpox resistance.  That is the public health target with cholera.  I am uninterested in breeding cholera-resistant humans (especially since without the techniques you dislike it would require killing off anyone non-resistant), I am interested in removing cholera or the precursors that allow a cholera outbreak.  Same with malaria and sickle-cell anemia.  If your point is that this very complicated, I agree.  Caution is required.  Banning a new tool?  No.