Found this thread through the excellent list of May songs.
I imagine the question about whether a new folk song about the past should be historically accurate has been fully discussed somewhere on Mudcat. I certainly remember discussion about The Band Played Waltzing Matilda in this context.
As someone who dabbles in writing songs about events decades ago, I prefer mine to be as factually correct as possible and have on several occasions made alterations to existing songs when I realise I've got something wrong.
With regard to John Condon, I agree with the comments made by Silas and Backwoodsman. The song also has a haunting melody though to my ears the main theme is perhaps reminiscent of a famous song from another genre?