I think the reason lots of posters are opinionated on Moyes' decisions at Sunderland thus far is that it's very similar to how he began at United - a club with such different demands and resources, yet with the same patterns of behaviour from him.
At United he came in and dithered in the transfer window, prompting people to speculate that he wasn't being backed financially - same thing happened at Everton, a club who broke their own transfer record the season after he left. At United the club's own transfer record was broken while Moyes was here, & Woodward has shown continually that managers are backed with massive finances at the club...
Yet Moyes did nothing in that initial window, bumbled around chasing Fabregas (& Bale?), and ended up signing Fellaini... a player from his old club, where he also tried to sign Baines in the same window.
And now we see him yet again seemingly only able of drawing in players he's previously found favour with (previous to his unraveling at United) - Januzaj, Mcnair, Pienaar, tried to sign Naismith, and the cherry on top being an unattached striker with 24 goals in 10 years...
Another big, and in my opinion, far more damning similarity, is the immediate lowering of expectations in a manner that after watching him do it at United, is so familar and actually seems quite calculated...
At United, within weeks of taking over the current PL champions and CL semi-finalists, he was claiming that he'd need "6 world class players" in order to win (or challenge?) the CL.
And now within weeks of taking over a club at the other end of the table, he's claiming that he can't get the players in good enough to 'make a difference' at the club - essentially blaming his tools before he's even begun the job.
Exactly the same at both clubs.
At United he was constantly trying to lower expectations. His now famous quotes about 'aspiring to be like City' while managing the current PL champions, 'making it difficult' for Newcastle etc.
At Sunderland he rocks up and announces that the club should expect a relegation battle - this is two games into the season, and a team that ended last season with great momentum and form.
Exactly the same at both clubs.
At each club he's at, he manages to cultivate an image that his job is somehow harder than it appears, and that it isn't his fault if things go wrong - at United it was 'taking over Fergie was an impossible job', 'the squad (of champions) he took over is somehow deceptively weaker than it appears' etc.
And now at Sunderland its, 'no-one would want to sign for Sunderland' - yet in January, Allardyce brought in a handful of players including Defoe and Khazri (who are both still there for Moyes) and turned their season around, with them finding good form.
Exactly the same at both clubs.
Moyes needed to come in there and bring a lift, that's what a manager is paid to do, and instead he's effectively insulted his entire squad (as he did at United) and lowered the expectations of the fanbase (as he did at United) in a manner that would suggest if he fails then it isn't his fault (as he did at United).
It's these similarities that make United fans (and many Everton fans) raise an eyebrow. And also, some United fans still believe/d that perhaps it wasn't his fault that he failed here, and so seeing the same patterns unfurl at Sunderland will cause them to change their minds, and thus feel the need to vent about it.
One thing's for sure - he needs to do a decent job at Sunderland, and if he's going to do that, he'll need to lift spirits, not deflate them. And he'll need to focus on the team and the club, rather than his own career.