Exactly what I was going to say — the whole story is a confusion between phylogenetic and sociogenetic (and even ontogenetic, arguably). For drunkenness to be a phylogenetic adaptation would require that humans were making alcohol long enough in our past that there has been time for genetic adaption to take place. But we’ve only been making alcohol for something like 10,000 years, as I understand it. That’s a remarkable speed of phylogenetic change. “Ah,” the argument goes, “but maybe it’s other types of poison, rather than alcohol”. Really? So ancient tribes routinely and reliably had access to the type of naturally-occurring toxins that inebriate but don’t kill, and had this access in a sufficiently systematic way that it could form the basis for an actual phylogenetic alteration?
It makes much more sense to me that displays of ability to handle toxins would be result in sociogenetic adaptation, whereby the rituals of drunkenness would become inscribed in cultural practices.