Incidentally, the "it's wrong to intervene" argument is NOT the argument Phlox uses for not giving the cure, it's that the disease is a genetic disorder, and so the "gods of evolution" have slated for the Valakians to go extinct.
So Phlox's rationale for his psychopathic actions is not "imperialism," it's pseudo-science.
And the differences between giving a cure for a disease and a military intervention are so numerous that I can't believe anyone would even try to compare the two.
Did Archer have to consider casualties of troops here? Or civilian deaths as collateral damage in battles? Or political balance-of-power calculations?
In other words, what was it costing him to give the cure? What was the dilemma?
There was none.