It's not hard to believe, because up until very, very recently, virtually every large scale epidemiological study showed that moderate drinkers outlived abstainers.
Now, yes, there has been a recent spate of studies showing that there were some confounding factors not controlled for in those studies[ which will be true for all epidemiological studies]. Socioeconomic status was always controlled for but maybe not perfectly. More, they have realized that many abstainers didn't drink due to various health reasons.
However, the case is certainly not closed shut as you and many make it out to seem. These are still not gold standard, double blind, placebo controlled studies. Therefore they are certainly imperfect. And furthermore, some of these studies recently grabbing headlines absolutely exaggerated their results [ and/or the media did]. In many of the studies, there was very little difference between moderate drinkers longevity and abstainers, even when all of the newly controlled factors were plugged in. Some still showed potential heart health benefits.
One study out of mass general last year found direct link/ pathway to The potential heart health benefits of alcohol where alcohol reduces stress via the brain. This seem especially pronounced in those with higher levels of anxiety and and stress.
Lastly, the long-awaited new US dietary guidelines is still going to say that moderate drinkers outlive abstainers and that there are heart health benefits to moderate drinking.
"the National Academies of Sciences, Engineering, and Medicine (NASEM) released a report that was commissioned to inform the 2025 Dietary Guidelines. It found that, compared to people who never drank, moderate drinkers had lower all-cause mortality and a lower risk of death from cardiovascular disease."
[ now, yes, this is a bit controversial. As there are accusations of the authors being funded by alcohol industry. However.... They rely on some fairly strong studies to come to their conclusions].
Cheers! 🍻