He probably had contact numbers, family photos, videos and information not related to football that he wanted private. He should expect that privacy. Now if the league furnished him a football business phone only, that would be different.
I thought I read somewhere that he had a history of destroying his phone every 4 months. I have no reason why, but that was his practice. In this case, he made the phone available initially, but after a while asked his attorney’s if it was ok to destroy the phone. They told him it was ok. As I remember, he agreed to give the league a list of all the people he had texted so they could get the data from their phones. Sounds to me that Brady had stuff on his phone that he didn’t want the NFL to see, stuff that probably had nothing to do with “Deflategate” but might be embarrassing otherwise. I don’t blame him.
From what he said, he had not only contact lists and numbers that he didn’t feel were his to give out, but contract negotiation stuff. Even the partial release has things he has been ridiculed for, and for which he has felt he needed to apologize.
The NFL has released irrelevant but embarrassing communications between McNally and his mother, Incognito and his friends, and others...quite selectively. They don’t do that to anyone that they are trying to roast. They also don’t reduce punishment for turning over phones.
Further, even Roger Goodell did not give up his personal phone in the investigation of his handling of the Ray Rice episode.