It does affect all players but as you say goalkeepers more.Doesn’t that apply to all players, regardless of age? I know goalies are criticised more than most so I do agree with your point. One mistake can cost the team a game. Midfielders can often get away with it. However, let’s use Henry as an example; his confidence has been completely shot, since the play off final. Has he recovered? I don’t think so.
Henry is gradually getting back but Eastwood's mistakes have massively affected his confidence.
My point really is that Stevens has been fantastic since he came into the team. He has not done much wrong ( and when he has the breaks have gone his way.
But nobody quite knows yet how he will cope with a couple of mistakes. Hopefully he has massive self confidence and will shrug off any downturns