The only thing I learned from this study is that the 20% of the Chinese can't drink.
good strategy -- there are time when every calorie you can get counts.
bad strategy -- its addictive and toxic.
solution? favor those who could consume it to avoid starvation, but would not touch it otherwise because it is so unpleasant (instant hangover).
Meanwhile brewing alcohol only started maybe 3k years ago in north western Europe so they are still figuring it out.
And poor north America did not stand a chance, bulk fruit/grain preservation via fermentation had never became widespread then it showed up fully refined.
Metabolizing alcohol yields aldehydes, which can and do cause double strand breaks in DNA. We normally have processes to repair the damage but mistakes will be made and build up over time.
There is no minimum safe healthy amount to consume.
Drinking alcohol just beats starving, nothing more.