I think it has to do with understanding the goals of beer manufacturing in an earlier era: they weren't targeting ABV ratios, and maybe understood the "strength

I think it has to do with understanding the goals of beer manufacturing in an earlier era: they weren't targeting ABV ratios, and maybe understood the "strength" of beer in a much less precise way than we do. Thus if you read that so-and-so person had 3 quarts of "strong beer" a day with their cheese and pork trimmings it might be jumping to conclusions to assume it was all in the 5-7% range.