The hate stems from fear that he's going to get the job permanently. You only have to look at the propaganda pieces from the local media to see why the fear is so real.
The 0-6 against Liverpool was worse to be fair. The last 20 minutes of the 7-3 against Arsenal was one of the most humiliating performances I've ever seen as well.
The saddest part is how many fans have no ambition any more. You could just about live with Ashley having no ambition because there's always the hope he will fuck off one day. With the fans I don't know how you fix that.