There is probably almost never no selection pressures. The problem is: what was the selection pressure? From the article you posted we see it's accepted humans in the northern regions ate a lot of meat. This provides vitamin D. Therefore no selection pressure for white skin from that angle.

So-called white people actually turn brown in summer by tanning. For any other creature that had white hair, blue eyes and changed from white to brown with the seasons we'd have no hesitation pronouncing it was an adaption to winter snow. Are we so convinced humans obey a different set of biological rules to all other species that we discount this idea?