'Offence' is probably not the best word. The song was written about Irish, English / Irish gangsters in Manchester by a majority Irish band. Misappropriation of the song by the occupation crown forces was unpleasant and unfortunate and I'm sure neither Phil Lynott nor Brian Downey would have approved of this or the many crimes committed by Brit marines and other regiments in Ireland . Just like I'm sure Tina Turner wouldn't approve of the misappropriation of her song by Rangers and Sevco racists and Loyalist murder gang, narco-terrorists. My knowledge of Tina's song predates the misappropriation and I'm not 'offended' by it. I'm offended by the misuse of the song but not the song itself.
All a bit of a moot point anyway as The Boys Are Back In Town wouldn't really be suitable for chanting at a match.