I think it is a bit confusingly formulated in the article. Facts in the common sense are objectively measured "information", whereas values are akin to facts in that they represent the objective truth perceived by people. That could be a single person's truth, as everyone has a certain way for seeing the world; or (as the authors argues), a number of other people share this view - this is when subjective observations become society values, norms etc. Therefore, by being shared by many people, values can become comparable to objective facts. I would argue they are still a different type, albeit no less or more important.