Fundamentally evolution is selecting for genes, not individuals, and there is no 1:1 relationship between genes and individuals.
Let's say that everyone has a skin color gene that makes them either red or blue. And a new predator turns up that only eats blue things. To you this is a tale about individuals, while it seems that an equally valid, and frankly preferable, view is this this isn't about individuals - it's about being red or blue and is a species level effect.
I suspect the underlying issue is that we are all terrible at unthreading cause from effect.
Words matter. Talking about "species level" is misleading because talking about an effect (blue phenotype) distracts us from the cause (a gene for blue).
And evolution is confusingly another step removed: the red survives because the blue did not.
Most of us struggle to see the counterfactual absence of a something.
The blue "species" never exists - our brains want to find groups and patterns. Our words mislead us.
The same thing is alluded to in the paper: the deaths of people without the gene is what is driving the gene to spread (through reproductive success of those that didn't die).
Reproduction is what matters (which death or sickness may interfere with).
Even the paper is confusing because it talks about 50 year old women (measuring survival bias; not whether they are expected to pass on genes at 50).
(reedits for clarity).
Also read this comment by a real biologist:
https://news.ycombinator.com/item?id=49734849
Have you studied evolution, or is this your own theory?
If individuals share some genetics, and evolutionary selection pressures act on genetics, then it follows, right ?
Not even close. Evolutionary selection pressures don't usually act directly on genetics. Perhaps you are incorrectly attempting to rely on intuition, and over-simplistic phrases like selection pressures. Intuition is incredibly misleading with evolution.
Your pink and blue example is actually a great model to work from. Think about the genes and the expression of those genes, and then think about what is being selected if all the blue animals are eaten.
Or think about what would happen if there was a mountain range, and pink animals were eaten on one side and blue ones were eaten on the other side.
Or think about what if one of the blue fathers has pink polka dots that gave it a 10% better chance of survival.
Always concentrate on watching that genes are passed on by reproduction - getting eaten doesn't have to be a problem if reproduction has already occurred (unless parental investment is needed or you get complicated like kin selection).
I am not a biologist. But 'The Selfish Gene' is one of my favourite books because of the concepts within. Unfortunately I think Dawkins went off the deep end later (with what I thought was religious zeal). The Extended Phenotype is even harder to read, but also worthwhile.
It is a fun topic because many phrases about evolution seem misleadingly about death rather than reproduction. And the meaning of the word evolution is absolutely twisted in everyday conversation. Ignoring the troubles with bible bashers. https://en.wikipedia.org/wiki/Survival_of_the_fittest - "fittest" has an unobvious meaning.
I don't think so. But it isn't my area of expertise.