I don't have all the facts - so I'm not even going to attempt to comment on this evenings incident. What I will do is make some general observations about my experience as a passenger at Manchester Victoria in the last few weeks.
Information
When things go wrong - platform alteration, delay, cancellation, whatever - there's just not enough communication to passengers of what's happening. The station is overreliant on the information screens of which there are too few, and which often don't give the information that a passgenger actually needs ("Which train stops at Chorley?"). There is a lack of staff on the platforms (often there is not a single staff member to be seen on platforms 4, 5, or 6 unless there is a train in the platform), and those staff there are, with a few honourable exceptions, don't know enough to provide meaningful assitance to passengers. At least once or twice a week, I have to step in to help other passengers work out how to complete their journeys when something has gone awry. Often this is after they've approached a staff member who has either said they don't know or, worse, given an answer which is flat out incorrect.
Environment
Platforms 3 - 6 are just nasty places to be. Always dark, and often cold and windy, there's a lack of shelter, and a lack of somewhere vaguely habitable for passengers to wait. There's also a woeful lack of seating for passengers who often have to wait quite a long time for their trains, because of delays and cancellations.
Seemingly illogical decision making
The best example of this is platform allocations. I know that, if I get the train home from Victoria, it could go from any one of the through platforms. I also know that the assigned platform could change at the last minute. Fortunately, I am physically able to leg it between platforms if I need to. Often, though, I just wait on platform three until I can see on Traksy where I need to be, to save myself the hassle. Other passengers aren't able to do that - for loads of reasons.
Bad advice
Standing on the platforms, I keep hearing passengers complaining that different staff have sent them to different platforms and all they want is to know where they need to go to get to their destination. It's not, bluntly, rocket science.
I'm a pretty easy going person and it takes a lot to annoy me, but I have every sympathy for these passengers who are sent from pillar to post based on bad advice, can't access the information they need, and are trying to deal with all of this in a crowded, unpleasent, noisy and possibly unfamilar environment. There's no excuse for the abuse of staff members (or anyone else for that matter!) but really, it was only a matter of time because Northern, TPE, Network Rail and others simply aren't doing enough to help passengers get where they need to be. Victoria is bad enough for passengers when everything is running perfectly - with a timetable change, disruption, and Christmas madness all happening as well, it's not difficult to see how tempers become inflamed.