Rouz hit the nail on the head.
What comes now is purely my speculation, however: I suspect building a tolerance to alcoholic beverages was much like building tolerance to consuming wheat or dairy products.
AKA at some point in history, a bottleneck event occured where food was extremely scarce, and those who were able to sttomach lactose, for example had an extra food supply, and those who couldn't stomach it passed away long before the advent of modern medicine or food production could keep them alive if they were lacking that trait in a particularly dire situation aka famine. Over generations, this gradual shift in reproductive dynamics resulted in modern human populations where rates of lactose intolerance are much higher in populations from east asia and the americas, who have not been exposed to dairy products nearly as long, relatively speaking, as many populations from the middle east and europe and also Africa. In contrast, in the distant past at one time virtually no human populations would have been able to stomach it because the human GI system was never selected for such a task (drinking another animal's milk and growing wheat is not something any animal, including humans until about 10k BC, did in the wild).
Now, it may not be the case that beer was popular as a source of calories in times of famine in certain populations. But perhaps the same principle applies, where those civilizations that have been exposed to alcohol for many more generations into the past of the history of human civilization have built up a tolerance to it because with each generation of exposure a certain number of heavy drinkers who couldn't hold the alcohol well would have died prematurely, or become drunkards whose children died from neglect, or nobody wanted children with.
Obviously, given the advent of modern medicine and civilization, this sort of selection across generations no longer occurs because, at least in the developed world, even if people suffer alcoholism, they can now get enough help to live a healthy enough life to even raise a family, and they do not have to worry about famine. However there is an unfortunate aspect to this, that people who happened to be born in populations detached from the old world are being exposed to products, particularly drugs and alcohol, to which they have had little chance in the past to build up a tolerance, or resistance against addiction, for. I hope they get some money out of the lawsuit so they can get help for their problem, and perhaps have the business thaat sells alcohol relocate so their community can live in peace.