I'd think of it in terms of a sort of species normative lifespan and indicators of aging. Let's say it's 80 effective years. What this study is saying that fact

I'd think of it in terms of a sort of species normative lifespan and indicators of aging. Let's say it's 80 effective years. What this study is saying that factors other than genes have much more more influence on whether you make it to (or even past) the normative lifespan/age. Not that the length of the generalized normative lifespan isn't a product of genes, or that individuals who appear as severe outliers aren't doing so because of genetic factors. But that the largest factor impacting premature expression of normative age or pre-normal-age death aren't genetically driven at the population level. I would note, however, that this result is going to be extremely influenced by the society being studied. If famine is widespread, then many genetic factors won't matter. Similar for war, etc. (And this is probably partially why socioeconomic factors have a big influence.)