I think it's likely that the WHO is considering people like me in their recommendation.
I have friends who can drink a beer, maybe two, and be quite happy and satisfied. This is a phenomenon I have never been able to understand, because even a small amount of alcohol switches my reward system to REQUIRE more.
If I have zero alcohol, I'm fine. But if I have one beer, I WILL have 7 more. For some portion of the human population (I've seen estimates at 15-20%), the concept of moderation is impossible - and for us, zero is the correct amount.
If the WHO said "drink moderately if you don't experience dopaminergic response to ethanol, but drink zero if you do", it would be more nuanced and accurate, but public health organizations need to target their recommendations to the LCD, as simply as possible.
It's the same as dietary cholesterol and salt. No health organization is going to say "run a double-blind study on yourself to find out if you are part of the population for whom dietary cholesterol impacts serum cholesterol, or sodium intake affects blood pressure, then consult this chart to see what our recommendation is for you" Instead they'll just say GROG SAY SALT AND EGGS BAD, NO EAT.