First let me say that I am new to MCM, I discovered it a few weeks ago and love this blog. I am also a big VY fan. Although I would not have benched him, this was a judgement call and there is merit to both sides of this argument.
I would't have benched Young for some of the same reasons raised on this site; a) he's a clutch player with a history of late game heroics, b) If he could have gotten one drive going the whole game could have changed.
I differ with many on here in that I would not have refrained from benching him out of concern for what it would do to his confidence. In fact, just the opposite. I wanted to see him gut it out to the end. It looked to me that as the game progressed he became more tentative. I wanted to see him eventually say 'screw it, if we're going down we're going down fighting.' I wanted to see that he would ignore the interceptions & sacks, ignore the smattering of boos, and hang tough to try to win the game. To me, benching bails him out of a very tough situation.
Another area of dissagreement is that I think that benching VY in favor of Collins is not that unreasonable when you consider the following: a) Young looked looked awful and was getting worse as the game wore on, b) the steelers do confuse opposing offenses, even ones with veteran QBs c) We've got a vet on the bench (where he belongs) who was the starter when we went 13-3 and beat the Steelers. If you think you still have a chance to win the game, one decent option is to play the vet who's beaten the STeeler before and see if he can get anything rolling.
I wouldn't have done it, but I don't think the decision makes Fisher an "idiot". I cannot understand those who actually think Fisher is trying to undermine his starting QB. VY has improved dramatically. This was just one bad outing. If he's really matured as much as he seems to have, he'll be just fine.