People have provided plenty of reasons but I'll restate them anyway.
We're a destination club because of our reputation for looking after our players. Because we value players as people not as footballing robots to be traded like horses to get our furthest advantage from.
But further, if one of your workmates is treated poorly as they leave the place you work it sends a message to everyone there that the people of the company aren't important to it, only the company itself. It slowly breeds discontent. Thats not us, we respect our players as people. Now whether this is in helping people who want to move for personal reasons, or any other part of our programs (sure buddy, take time off through finals) it builds a culture of respect and decency, and that helps to attract people in non-footballing roles even attract and retain fans. The whole institution and organisation is stronger because we take small losses occasionally on trades and don't battle like bastards on every small potential advantage. There is barely a difference between pick 10 and pick 12, it depends how those players develop, and we are creating the best environment to develop people and players in.