They act on behalf of their constituents in dealing with UK gov, civil service etc. etc - why shouldnt they be paid for that? They are Irish MPs but they have no place in a parliament that makes decisions for Britain only.
The people of Fermangh/South Tyrone voted in an MP once and when he died Westminster changed the rules so his ilk couldnt get in again - and telling the nationalist people that we dont want your type here and we will change the rules to reflect that. Westminster has always acted against the nationalist population and you want them to go sit in their parliament, cap in hand?
The people in the north elect candidates not to sit there. Sinn Fein are doing as the people of their community wish.
Who are you to tell the people in the north how to live? Your kind turned your back on them long ago, what do you give a fuck?