Happy for Danny. Whatever his reasons for leaving Boston, clearly it was time for both him and the organization and it's good he was able to leave on his own terms and find something else that suited him better at that point in his life. People join and leave organizations all the time, for all types of reasons. I've quit well paying jobs for reasons as varied as boredom, stress, nearly having a nervous breakdown, higher pay. better culture, just to name a few. I'm sure so has everyone else. It's just that in sports fandom everything gets taken by fans personally.
I'm happy for what he accomplished at Boston but if your heart's no longer in it then it's time for a change. It's your life, nobody else will make sure you live it the way you want but you. He's now part of the past...as a fan my focus is on what Brad is doing.