I think the objection is the completely objectionable way in which he treated 2 MPs when they raised perfectly reasonable points about the expenses stuff. I saw one of those incidents on the television and wasn't impressed. From what I can gather there is a feeling that he has done this many times before, but less noticeably so. Maybe there is an element of scapegoat in this as well, but that's not the only/main reason as far as I can tell.