Here's what Cam Neely said directly. Note that, before the signing, Cam said that he spent a bunch of time with Miller and vetted him, and felt ok that Miller was sufficiently penitent.
The decision to sign this young man was made after careful consideration of the facts as we were aware of them: that at 14-years-old he made a poor decision that led to a juvenile conviction. We understood this to be an isolated incident and that he had taken meaningful action to reform and was committed to ongoing personal development. Based on that understanding we offered him a contract.
“Based on new information, we believe it is the best decision at this time to rescind the opportunity for Mitchell Miller to represent the Boston Bruins. We hope that he continues to work with professionals and programs to further his education and personal growth.
“We owe it to our fans, players, staff, partners and community to make sure that our practices and protocols are in keeping with the ethos that we demand from ourselves and as an organization. As such, we will be reevaluating our internal processes for vetting individuals who wish to earn the privilege of playing in the National Hockey League for the Boston Bruins.
There's a ton of stuff *we* don't know, but what we absolutely do know is that Gary Bettman, a Certified Scary f***ing Lawyer, felt 100% comfortable dropping the dime on this kid, and everyone *immediately* got in line. So we can safely assume that *he* knows enough to make this determination without fear of contradiction. The fact that this kid was USHL player of the year last year was not enough to save him.
Also note that this wasn't the press jumping on this story. It was Bettman himself, unprompted by the media, taking Cam Neely behind the woodshed in public for not doing his homework, and Cam Neely going "yup, message received."
We can speculate endlessly, but there's no reason to believe that Gary Bettman is speculating.