It's difficult for the mass media and supporters to judge keepers. It normally takes a flashy save or a comedic error for them to lean either way. When you have goals like the Frankfurt second goal, which is not an obvious error as such, people don't tend to focus on the keeper much.
Thing is, while the lay-man may not see it, you have a wealth of analysts, keeping coaches, etc. around the club who can and should be noticing this. How a keeper who has not saved us in any big games for years now is never questioned is beyond me. He makes one or two of those handball saves in 1v1 situations where the ball hits him and people go crazy about how good he is.
Which other position would this be okay? Where you don't show up in any big game? While it's not the keepers job to pull out miracles game after game, you expect a top keeper to be an integral part of making it difficult to score against you, and be making top saves regularly. MATS is just fooling everyone into being his biggest supporter, it's pretty amazing.