It’s certainly interesting. My initial reaction is that “lifetime abstainers” is still a sufficiently distinct group from the continuum of moderate to heavy drinkers so there might be other confounders. I wonder if a study like that exists? I personally know only a handful of people who never drink, and it’s either for religious reasons or, in one case, the person just likes to put themselves at odds with society in various ways, including never drinking.

It might be that people with worse health tend to abstain from alcohol more often because they feel worse after consuming it. Or that some substances consumed with alcohol, like all other compounds present in wine except for alcohol might have some protective function when consumed regularly.

There are way more possible explanations better than "some amount of ethyl alcohol is actually a little bit beneficial".

Ethyl alcohol may cause harm to the body, but these findings do suggest that the total effect on health is positive.

Interestingly, (wrt. https://www.jacc.org/doi/10.1016/j.jacc.2017.06.054) the 15 drink-a-week threshold that's often quoted as a kind of limit to safe drinking puts your all-cause-mortality risk right at that of lifetime teetotalers. The utilitarian implication is that, after 15 drinks a week, you really are causing harm relative to not drinking at all. So its costs outweigh any benefits. But that implies that there are benefits. These may be very subtle.

Perhaps alcohol is part of a balanced diet. It arises during digestion. You find it in ripe fruit, a significant part of many primate diets. It also appears to be part of the typical diet in many of the regions of the world that have the highest life expectancy. Would they live even longer if they could shake the habit? Maybe we could study that genetically. Are these cultures just healthier for other reasons, and thus more tolerant of alcohol? It would be like the entire society has shifted along the curve shown here https://www.jacc.org/cms/asset/f6fb55ac-3d9d-4e40-8128-ec785....