Comment by mediaman

Simple mechanistic explanations in biology are often wrong. For example, oxidative stress does not have a linear no-threshold harm.

For alcohol, almost every big study has shown either no discernible effects going from zero to 1 drink per day, or actual slight benefits going from 0 to 1 that then reverse when increasing beyond that. There is not strong consensus which of these is true, but there's definitely no real evidence that 1 drink per day is harmful as measured by all-cause mortality.

See GBD 2020 in the Lancet (which showed a slight J-curve), Wood in the Lancet 2018 (optimally low risk at 100g ethanol per week, or ~1 drink per day), Zhao in Jama (no discernible negative effects at 1 drink per day, no benefits either, no J-curve), and the latest National Acadamies review showing lowest all-cause mortality at about 1 drink per day (so, a J-curve).

Alcoholism has tons of negative effects. But these seem to start at around 2 drinks per day and rise rapidly from there.