No, 34years I don't live in or come from Manchester. Yes, I am aware of most of the things you say, including the attack on the technicians.
I simply do not understand why the city council sought to accommodate the ticketless fans by providing big screens. If they did not want them in the city it might have been better to encourage them to remain at home by stating quite clearly (and well in advance) that they would not be able to see the match if they travelled. This action could have been reinforced by the temporary closure of pubs and bars in the city centre on the day (which could and should have been done on police advice). At least if the Scottish idiots did still turn up they would have had nowhere to watch the match (if indeed that was their intention), nowhere to get drunk and less reasons (though doubtless they'd still have found some) to fight people.
The sooner the authorities realise that the watching of football should only take place in football grounds where proper facilities for containment exist, the better it will be for all concerned (and for many not so concerned).
As for the city council's latest decision, I am not at all interested in football and have no idea which Manchester councillors support which, if any, team. I would be extremely surprised if the council's decision was in anyway partisan. It seems to be a sensible reaction to prevent a recurrence of a problem which should not have occurred in the first place.