Not explicitly mentioned, but is linked from the article:

In Europe, the understanding is that this mandate actually encourages good husbandry on farms. It’s in the farmers’ best interests then to produce to cleanest eggs possible, as no one is going to buy their eggs if they’re dirty [1]

So in Europe, you need a clean environment as you're not allowed to wash the eggs. I find this equally compelling than not wanting to wash the protective cuticle off that protects against bacteria.

[1] http://www.forbes.com/sites/nadiaarumugam/2012/10/25/why-ame...