Anybody that's ever played any sport at any level, but particularly at the higher levels, knows that the worst thing that can happen to you is when a coach ignores you - it means they've concluded you aren't going to get any better and the coach moves on to players he thinks can get better. Usually players that get the coach's attention are the ones thought to have the potential to be much better. And if you stagnate, the coach gets disappointed and ignores you, which is truly the kiss of death.
No one knows what goes on behind closed doors with the players and the coach. For all anyone knows, Boeheim has communicated to Roberson that he's going to ride him like a mule publicly and Roby has said that's what he needs, go for it. Does it make me cringe a bit when I see it on tv? Of course. But the fact is no one knows their dynamic when no one is looking. Unless you're in that locker room or a fly on the wall in closed door meetings between coach and player, no one other than Roby and JB knows.
As for bullying, it's a ridiculous charge...bullying happens among peers. And no one knows if Roby feels humiliated or berated or demeaned. Maybe he does maybe he doesn't.
On Cooney, as I see it Boeheim defended him because he thought he had reached his potential and was doing as best as he could. With Roby, my guess is Boeheim has, and still does, believe that there's much more in the tank. Roby does just enough in some games to spark Boeheim's belief in him and then just not enough to spark his disappointment.
Players look at things very differently than fans.