You shouldn't sing any song you are uncomfortable with - as you obviously are with these, but in the end, the choice has to be the singers.
There are excellent versions of Botany Bay if you are not happy with the usual one.
The version of The Wild Rover usually heard in the clubs is the one kicked to death by The Clancys, Dubliners... et al - have a look at Mary Anne Carolan/Pat Usher's version (if you can find it), beats most popular songs in the club repertoire and hardly ever heard.
Fields of Athenry - there are far better songs for telling the Brits what a balls-up they've made in Ireland - try The Row In The Town!!!
Where have all the flowers gone - hackneyed, maybe, but inoffensive.
"pop song or country song or heavy metal - these seem to be fine with most clubs."
Confirms my worst fears - are things really that bad over there? If shit like this is acceptable in folk clubs, Tom Lehrer's Irish Ballad should be at the top of your list - at least it has humour and imagination.
There should NEVER be a 'banned list' of folk songs in folk clubs, if the repertoir works for you sing it, and when the village idiots start popping their cheeks during 'Larks', tell them to piss off.
Jim Carroll.