It's pre-emptive damage control.
It's a dangerous game of poker where he probably knows a bluff isn't going to work, and it's probably due to this investigation by the state potentially having enough evidence to prove everything true. You generally take the 'can't comment' stance if there's any chance of getting away with deniability. I think the evidence is stacked against him given the amount of hearsay, the dwindling public trust in the company as a whole, and many more factors.
He may be put in a position where all he can do is admit to knowing something but failing to act in time of need. It's the best means of saving face, given that any deniability may just dig a deeper hole than admitting he knew and wasn't aware of how bad it got. His hand is already caught in the cookie jar, so to speak, considering his close personal ties to the accused, and how it's literally his responsibility for having kept them around. Shit like that can't stay secret, and 'no comment' is not going to help him publicly.
At least with his latest statement, and with support from tweets directly from Cher after talking with her, he's creating an image of deniability in the form of inaction, rather than ignorance. That is his best move right now, given that the evidence for what happened may already be too damning to deny.
I would probably be more convinced of a 'no comment' move if he weren't actively founder/CEO of a new startup that he needs to continue to build trust in. If he was just retired and didn't need to be in the public eye, then sure, he could just fall on deniability.