So what if he moved to Milan? These players are also employees, there are other factors to think about when you make your next career change not to just appease fans.
He always gave his all to Juve and that should be enough to earn our respect. Truth is choices are personal, whether it is money or anything else. And why should it matter? If a player wants to leave for whatever reason then leave, he will be of no good to us if the atmosphere is not right. As Juve fans we should only consider the players time with us. What they did before or after is immaterial.
No player is bigger than the club. Club always moves on. Juve's bandiera? Cmon. DP is a bandiera. Buffon is a bandiera. It will take a while until there is another player that can even fill those shoes. I love our players but there is no foreseeable Juve bandiera after Buffon. Everyone is expendable.