You're the one who's defining normal badly. If you are told someone, or even all the people in a country, is/are "taller than normal", would you think they were all above 1.853 meters or whatever, or that they were all outside the range of normal heights? Because that's what anyone else would assume.
The Dutch, as a country, are "taller than normal", and this is a fairly common point to make about them. I've always taken it to mean that their population average is somewhere above 1.852 meters or whatever, not that they are alarmingly, abnormally tall (which they are not).
So I think this example fails, at least. The original article is trying to make the point that Europe's soil is alarmingly, abnormally dry.