Yes, I think that health is a result of genetics and that certain people are predisposed to having better health due to genetics. I think that science should look further into how genetics can and does keep people more healthy and try and find a way to use genetics to make more people healthier.
A person's health is a mixture of several factors - diet, lifestyle, exercise and genetics. While what you eat and how you live, how active you are, will all contribute to the chart of fitness, it is your genetics which plot the initial form. If you're predisposed to diabetes? You'll have to take that into consideration, for example.
The reason people think poor health is genetic is because they do everything they are told to do by doctors and their health fails to improve. Therefore, it must be a result of genetics; it's beyond their control. The main reason this fails is because a single diet cannot be pushed on the entire human race. Natural selection has been at work for a very long time--if you were genetically predisposed to certain diseases, even obesity and diabetes, then your genetics would have died out a long time ago. An obese person that continues to eat a high-carb diet pushed by their doctor will continue to fall into the blood glucose/insulin trap and just become perpetually fatter and sicker. That is, until they starve themselves and feel miserable for a few years just to shed a couple of pounds. Obviously, the stagnant nature of modern living and sitting 8 hours a day doesn't help, but I'd hardly call "exercise" the cure to any obesity problem. Your body should know how to manage weight. How does it make any evolutionary sense that the food we eat makes some people so fat and sick that they wouldn't even be able to hunt or forage for their own if there wasn't a grocery store around the corner? Pro-tip: it doesn't.