From what I am reading, he wants to join Dortmund. There are no guarantees of a starting shirt with Juve. Let's keep in mind that although Ciro has had a great season in Serie A, he is playing at a mid-table club right now that plays a style that is totally different to what Juve play. He has absolutely no competition for a place in Torino, so unless there is an injury or suspension, he was the starter every week.
And if they can get a sizeable profit for a player who barely ever played for Juve, then so be it. Provided that the money is used to get top quality players like Sanchez.
This is very reminiscent of the Giovinco situation from a couple of years ago, where people were ranting and raving about bringing him back, they shouldn't have to pay so much for a player who was their to begin with yada yada yada.
They MUST use these funds towards a top winger though, if that is their plan.