I wouldn't pay too much attention to social media, and especially forums where there is a childish hounding of anybody that wants to remain positive be it the Manager or certain players, to such an extent that most decide to give up because it's just not worth the hassle, group bullying at it's finest.
And i'm sorry your comment about Moyes after the Liverpool match is laughable, unless you think everybody that attended that day was an idiot, the one great fear during the 'glory years' was how we'd cope when SAF left because as is the norm in that situation(and it happens in most if not all sports)the wheels would come off initially, whoever the Manager was, you could almost predict it.
I'd hazard a guess that at least 75% of those there for the Liverpool game were also at SAF's last match where he gave that rousing speech post-match saying the club and Manager were gonna need the fans support more than ever., do you honestly believe every United fan that attended the Liverpool game thought they knew better than SAF?