sorry i have plagarised this, but perhaps it can meet some of your points.
so no totally right and no totally wrong. I would have been against sending British troops at any point.
In 1920, the British Government agreed to let Ireland leave, because of the protests and unrest in the country. However, there were more protests among the large Protestant population who wanted to remain part of the United Kingdom. As a compromise, Ireland was divided. The majority of Ireland became a new country, and Northern Ireland was kept as part of the United Kingdom, even though it had a sizeable Catholic population who opposed this.
Northern Ireland was given a large amount of autonomy and had its own Parliament and Prime Minister. However, since there were a slightly larger number of Protestants than Catholics, the unionists always held a majority in the Parliament, and the "majority rules" nature of it meant the republicans were frequently excluded. Neverthertheless, Northern Ireland was relatively stable up until the 1960s.
The growth of unrest in Northern Ireland led to more British troops being sent in to help the police deal with The Troubles, as they became to be known. This didn't always work out, especially at Bloody Sunday in 1972. Soon afterwards, the British Government abolished the government of Northern Ireland and placed it under direct control (although Northern Ireland was still represented in the British Parliament). The Northern Ireland government was recently restored, with the unionists and republicans sharing power.