“we even started to wear clothes to protect us from radiation. “
Not in article.
Modern humans also invented tailored clothing during this period, with archaeological sites containing not just hide scrapers but also sewing implements like needles and awls. This clothing would have allowed for greater mobility while providing coverage and potentially protection from increased radiation.
Lets get to the heart of the matter. A model was built on a few data points of a complex system. Just like all the climate models that proved global cooling, warming, changing.
A model like statistics never gives you an answer, at best it might give you another question at best.
They built a model here on a few datapoints. The researchers hopefully understand this (sometimes I doubt this) but the public does not.