I'm somewhat ambivalent about people being discouraged from expressing their negative feelings very strongly here. Too much hating and complaining can turn a place sour, but sharing your strong feelings, both positive and negative, are an important part of reacting to art--but I wholly agree with this part of the statement: "I would like to see scans_daily become more of a constructive celebration of comics."
I guess I just see some bitching as being constructive, in a roundabout sort of way. This isn't a concrit community for creators--it's a social space for readers.
It would be nice, I suppose, if, when expressing intense dislike of a work or a creator, people were encouraged to lean on the side of articulating what makes them feel that way.