Unless we are going to start referring to or reclassifying typing on a keyboard for 8 hours a day as strenuous physical activity (which it is not), coding will never be a blue collar job. Blue collar jobs by definition are classed so by the large amounts and types of physical exertion required to perform them along with the location in which that job is undertaken (mostly outside or in workshops). White collar jobs on the other hand refers to work that is generally of a cognitive nature and doesn't require much in the way of physical labor and are generally done in offices(don't get me wrong blue collar jobs require cognitive processes too but they also involve PHYSICAL LABOR as a KEY component).
The article would be better if it had said "blue collar work is going to be replaced by white collar work as the pillar of civil middle-class society". The title of the article currently is just plain wrong unless they are incorrectly referring to white and blue collar as some form of reference to a class system/exclusivity system based upon how many workers perform a certain type of task (e.g white collar jobs only employ a small high earning portion of the population whilst blue collar jobs employs the masses on average incomes).