I can't really blame the dispatchers in most cases, but I think we can reasonably blame the railroads for allowing situations like this to both occur and persist for an extended period. Obviously, meltdowns happen on occasion, and I can't blame a railroad for not wanting to turn away presumably high-dollar traffic. I wish that VIA, Amtrak, etc. would get payments to at least cover the resulting passenger inconvenience, if not to make up for some share of lost revenue (fraught with difficulties as such would be), but I can at least understand that lines can get jammed up because Reasons.
What I can blame them for is not turning around and investing either in their physical plant (new double-tracking or additional/longer sidings to accommodate the longer trains) or in their fleet (breaking some two-mile trains into two one-mile trains, albeit at the cost of some of their operating margin). Some blame can also go to the amount of track that has been ripped out over the years (which is not to blame them for all of it...dispatching improvements (such as from computers) and a natural decline in some markets likely justify some reductions on this front, and I think we can also blame the railroads for not trying to negotiate better policies with respect to taxation of tracks.