When a coach benches a player, he usually gets one of two different reactions.
1. The player gets pissed off and wants to prove that the coach is wrong. So he works his butt off when he gets some playing time and works his way back into the starting lineup. You could make the case that Randolph's big game yesterday was an example of that. Even Curry had a huge game soon after being benched.
2. The player sulks. This is kind of like the kid that doesn't get his way and decides to take his ball home to punish everyone else. It's a very immature response.
I think Isiah was trying to get reaction #1 and bring the best out of Steph, but he got reaction #2 instead. There may have been other things at work, but it sure looked bad.
A coach has to be a bit of a psychologist. Heck that's even true of managers in business. Part of the job is understanding how to motivate people. It's not an easy job because not all people react the same way to the same techniques.
I know some of you guys are going to get pissed off about this comment, but the timing of this latest ankle injury (perhaps even having surgery and being out 2 months) looks a little bad also. I don't doubt he's hurting a bit. But this coming to a head right after he made some comments about his role on the team makes it smell like a way of punishing Isiah, a way of avoiding losing, a way of saying he doesn't like his role on the team etc.....
We'll get more info in a few days, but I think you can at least understand why some people might be skeptical about the motivations and wonder whether this couldn't wait if he decides to have surgery right away.