I think Storm is correct in the literal sense. Rogue doesn’t have the sniffles, her body is “healthy”, it’s all functioning correctly. The fact that Rogue kills people she touches isn’t a health problem, it’s a problem with what her species is. You don’t call a lion sick because it kills zebra. There’s no “cure” for it.

Can a program be created that would turn Rogue into a homo sapiens? Yes. But I think Storm is objecting to the language of calling that a cure.