I'm not sure you're final paragraph is correct. There were over 200 deaths in NI related to the troubles in the 3 years before Bloody Sunday. It wasn't in anyway comparable to the poll tax riots. The situation had seriously deteriorated since the introduction of internment in August 1971.
Part of the problem was that the Parachute Regiment was entirely the wrong unit to be deployed in such a sensitive situation.
I'm reluctant to go into the where it all started and who shot who first discussion as I don't know how helpful it is to this individual case or
the wider moving forward process, as a whole. Internment had been introduced as early as 1964 when the civil rights movement first raised their heads.
However if you are interested and I do agree that the context of what was happening in the lead up to this is hugely significant, have a look at the timeline of events leading up to
January 1972.
https://en.wikipedia.org/wiki/Timeline_of_the_Northern_Ireland_Troubles_and_peace_process
It makes grim reading.
First bombings 1966 by the UVF killing an innocent Protestant woman.
July 13th 1969: RUC beat 67 year old man to death at riot/civil rights march clashes. Some say this is the first recognised death of The Troubles.
Aug 5th UVF plant bomb in The Republic of Ireland.
Things deteriorated terribly in 1970-1971 and the first soldier was shot in February 1971 and UDR soldier was killed in August 1971 after 14 had been killed by British soldiers, 11 in the Ballymurphy massacre.
etc., etc., it really was a grim period, but looking at the context of why a community had barricaded themselves into what they called Free Derry, they were not only protecting themselves from The Unionist police force and UPV counter demonstrators, but also the Army who were supposedly sent to protect them as equal citizens.
It is hard to comprehend now, for any of us living in a normal society. Society in Northern Ireland was so unequal and people were being beaten for protesting.
I just hope to God those days are over for good.
I don't think either side comes out of it very well, but the The Crown should have been impartial and the rule of law should have been upheld for all.
I hope your present government have long memories and have learned the lessons of ignoring that part of their Union for so long.