You're missing the point Jonn. No sense continuing this. It seems like some fans just constantly rip managers - they're never happy and nobody does a good job at it.
I've always struggled to know how you develop those opinions without considering that manager v. his peers and without considering all the correct calls they make. It's a pretty complex position and I don't even pretend to know what decisions the manager has full control over v. the ones he doesn't and thus I never feel I have remotely close to enough information to make an informed opinion - so I just don't.
IMO, managers and umpires are similar. Even if they are well above average - people still complain and suggest they are s*** at their jobs (often while in the absence of facts). When the fans favourite team wins, you hear nothing about either of them, but when they lose, the bitching starts.