In the folk tradition (which I believe Eric Bogle subscribes to) minor edits and alterations to suit the tempo or style of a particular singer are acceptable, but to delete half the song to deliberately remove its core meaning and message is grossly insulting and offensive in the extreme.

All part of the Folk Process I guess, which knows no ideological boundaries. First thing to go in a song are the more laboured conceits of the original writer, the core meaning and message if you like, which are wholly irrelevant to the individual experience of a song in a wider societal context where such heavy handed sermonising is collectively frowned upon in favour of a more pragmatic approach to such matters.