The Fenians were an Irish nationalist organization founded in the US that encouraged revolutionary activity to overthrow British rule in Ireland. To do that they basically caused trouble for the British, hence burning down colonies, and doing basically all the things that they could possibly do to regain their freedom, and seek revenge for all the trouble that they had caused them. Although there were many acts of violence, illegal acts, rebellions, deaths of innocent civilians and invasions on British colonies. What they were doing was for the betterment of Ireland in the long term. Anyone in place of the Fenians might also do the same thing to obtain freedom. Freedom Fighters fight for the freedom of their country, the events leading up to freedom may be devastating or tragic, but the sweet scent of freedom overcomes it all. .
During the times of the Fenians, there were many acts of violence; on of the most harsh one was the assassination of Thomas d'Arcy McGee. He was a poet and a politician, and at the time he was harsh critic of the Fenians brotherhood. Most Irish people were in favor of the Fenians, but he, being an Irish wasn't supportive of them. Just because he was in a higher position, he thought he would be able to make statements against the Fenians, and nothing would be done about it. One statement he had made was "The only way to destroy them is to cut them out by the roots and burn them into powder." Soon after that, April 6th 1868, he was shot in the head and died immediately. This just proves that part of the Irish government at the time was corrupt, and supported British rule. Since the Fenians believed in having a free country and taking revenge, and thought that people who are against it or are a part of the British republic, they shouldn't be counted, and this was the result. .
In 1866, the Fenians attempted another raid in Canada East, The Pigeon Hill. This was right after they had failed the raid of Canada West.