I've been trying to figure out why there's this constant bickering and pettiness among UK Mudcatters who are otherwise very nice people. I've seen similar conduct in only two other places - in orchestras, and in church choirs.
Could there be a connection?

From your saintly position of never having 'bickered' or been 'petty' with anyone - Joe you may have missed the obvious connection that Joe Offer was present and sitting in judgement, at all of the examples given above.

Am I really alone in finding these generalised and insulting comments about UK contributors more offensive than anything I have seen from any of our guests?

Comments that only tell us where Joe Offer is coming from. Are the witches only to be found and hunted in the UK? I rather think not but the UK witches do rather mess-up the ideal vision that Joe is trying single-handed to impose upon the forum. UK folkies (I suspect like folkies every where) are very nice people who have just always bickered and been petty.