Even excluding violent and chemical death, the third cause is cancer. Alcohol is classified as a carcinogen by IARC[1], the WHO[5] and the CDC[2]. I'm not well read on the subject - nor particularly well researched - but a cursory glance shows metabolic byproducts as the main culprit, though there are other factors.
As to "beneficial effects", keep in mind that the trace amounts of something healthy would pale in comparison to the negative effects of the alcohol, which is much less of a trace chemical.
Plus, other lifestyle choices could give a false positive[4]. Stuff like eating properly and exercising might not be properly controlled for, giving an unrealistically rosy picture.
The point about eating properly and exercising - that’s irrelevant since it’s not mutually exclusive with moderate drinking. You can drink moderately AND eat properly and exercise. The point about alcohol being a carcinogen is sort of irrelevant too since apparently it’s not enough of a carcinogen to affect longevity
As to "beneficial effects", keep in mind that the trace amounts of something healthy would pale in comparison to the negative effects of the alcohol, which is much less of a trace chemical.
Plus, other lifestyle choices could give a false positive[4]. Stuff like eating properly and exercising might not be properly controlled for, giving an unrealistically rosy picture.
[1]https://publications.iarc.fr/62
[2]https://www.cdc.gov/cancer/alcohol/index.htm
[3]https://en.wikipedia.org/wiki/Alcohol_and_cancer
[4]https://www.health.harvard.edu/blog/is-red-wine-good-actuall...
[5]https://www.who.int/substance_abuse/publications/global_stat...
(The first page has a downloadable PDF. Didn't link directly because it auto-downloads, at least for me.)
EDIT: link formatting, removal of extraneous "keep in mind".