yep, Ed...we have discussed it a lot. There has even been a catorization of the categorizers...into 'lumpers' & 'splitters'...(you know the old line..."there's two types of people- those who divide people into types, and those who don't")

The thing is, I believe that most people use categories everyday, but some want categories to reflect their 'personal' habits & attitudes, rather than being expected to follow some logic or order.

The Irish musicians you have met have a long-standing notion of how that music should be played...pace, tune, intonation...ever order of tunes sometimes! That is what 'tradition' MEANS... other ways are not exactly wrong, but there is, as you have seen, some resistance to gratuitous change.
..(I have similar reactions to hearing old familar songs "bluegrassed" --thus changing their entire character. I wonder why they WANT to play "Red River Valley" at double tempo with driving banjo!)

I do know that music does change over time...'folk processing', they call it, and I no doubt do some of that myself...but to use a phrase of my own coinage, it bothers me to have the Folk Processor set on 'pureé'.

I am admittedly in the conservative camp in this debate, but I have VERY detailed reasons and justifications for expecting certain venues and institutions to pay attention to the categories. I don't have any right to tell them what to play, who to hire, what to record, how to write...etc., but I DO claim it is careless -bordering on rude- to NAME the genrés in a slippery, self-serving way.

The cuckoo is renowned in song as a sneaky bird who lays her eggs in another birds nest and pushes the owners eggs out. That is a bit like I feel when someone writes a song about their navel, or changes words and tune to a traditional song, and calls it 'folk'. So, ummm...what am I now to call those old songs I like? 'Folk' was a useful term for a number of years, so was 'traditional'...now they are telling me Mary Chapin Carpenter is 'folk' and Bob Dylan is 'traditional'...*sigh*

So...perhaps in some venues, your group might issue a disclaimer, as Phil Cooper & Margaret Nelson do when they perform... Margaret says.."yes, I 'messed with' some of these songs, so don't be surprised is they are a little different than you are used to.".......That helps ME decide whether I want to buy their CDs or go to their concerts. 'Messing with' is not exactly a category, but it sure makes things clear!..(and some of their 'messing' is ok)

[incidentally, my other life is woodworking...and you ought to hear me when people (especially dealers)..make up cute names for wood just for advertising purposes, or use already 'known' words like Walnut & Rosewood to refer to trees that are NOT in the Juglans or Dalbergia families!....and there are similar disputes in the "Freeware" newsgroup where some want to advertise their ad-supported programs and get yelled at by those who want FREE to mean NO strings attached!...it goes on & on..quilters, antique collectors, Civil War buffs, SCA groups...ALL have debates about inclusion & exclusion of items, practices and categories]

It seems to me that there is no end to it, as people are simply wired differently as to how they see things............but..*grin*,,you DID ask!