I think this is probably due to people suffering from the just-world fallacy. Most folks like to believe that if you do the right things and consume the right stuff you'll have a long and healthy life when the fact of the matter is that luck/randomness plays a much larger role in your health than most people would like to admit.

You can control your luck a bit though. Granted you could be in perfect health but roll a 1 five times in a row and get a heart attack when you are 40. Or you could be crushing junk food and alcohol but you just keep rolling 6s and make it to 80.

If you look at the sequence of events that happen to trigger a heart attack, it becomes really clear how big a role luck is, but still you can mitigate each step. Studying this stuff also makes your body seem like a walking time bomb.

One hundred percent. I work in film, and recently had an argument with a friend around this point. He's incredibly healthy, and frequently works a large number of unsociable hours. I was pointing out that filmmaking hours make no concession for family or age. He'd convinced himself that he'll have no more difficulty doing 80 hour weeks in his forties and fifties than he does in his mid thirties, because he 'takes care of himself'. The implication being that everyone could work those hours if they just ate better and held multiple martial arts belts as he does. It was no use pointing out that he'd confused cause and effect.

I dont think this is right... most people I know care more about not doing the "wrong" thing than feeling entitled for doing the "right" thing.

You’re probably right but it’s also true that that is a very (probably unintended) cruel worldview that thought to the end claims all those suffering had it coming, and as such deserves to be called out and those having it should reconsider.

One should acknowledge the role genes/luck play in disease, while also admitting that there are a few foods about which there is more or less consensus they are very bad for your health. So you can roll your eyes if someone suggests eating kale sprouts will cure all your problems but don't just keep eating junk food as if the opposite of their take must be good.