The cardinals and bishops are not the pope's children. They're his colleagues and, yes, his subordinates. And if they're going to participate in public criticism of him, it isn't unreasonable to expect the same in return. 

Reforming the Curia is a political matter and to succeed in politics one needs informed public opinion on one's side. Too much harm has been caused over the years by institutional secrecy in the Church. The negative elements in the Curia thrive on it. Francis wants to change the culture of the Curia, and that requires transparency. In this, as in most areas of life, sunshine is the best disinfectant.