What is to be done with sick people who are sick b/c of genetics and not their own bad habits?

I am talking about responsible, clean living people who come down with ailments such as MS, ALS, cancer, strokes, Alzheimer's Disease, Crohn's Disease, arthritis, etc. We always hear about how people with bad health brought it upon themselves through smoking, drinking, promiscuous , etc., but what about those who didn't? It's easier to sleep at night believing that all the sick in America got that way because of bad habits, but it's harder to deal with the fact that innocent people become ill and can't get preventive treatment (incidentally an emergency room visit is not preventive, ongoing treatment), so how do we sweep this under the rug before our argument for denying others help is partially invalidated?