So let's get this straight: The author takes a single critique of Danish culture. Then asserts that this demonstrates that Danes can't be all that happy, and therefore concludes the Danes really just have low expectations.

Then the author notes that low Gini coefficients tend to be considered a good thing for happiness. But the author decides that actually low Gini coefficients (combined with Denmark's shocking ethnic homogeneity) are actually a bad thing, so Danes have even less excuse to be happy.