My experience is that objection to the term "source singer" is coupled with an objection to the use of "traditional singer" to do describe anybody other than "source singers". People who just 'sing traditional songs' are therefore (I think) demoted to being mere "folk singers", although how one is supposed to differentiate between folk singers who sing traditional songs and folk singers who don't is unclear.

Clarity and efficiency of language is very important if the general (national) bemusemement towards the genre is to be combatted. So for my money "traditional singer" = 'singer of traditional songs' and "source singer" = 'a traditional singer whose repertoire is drawn directly from the oral tradition' is the best way forward (the former being something people can aspire to be, unlike the latter). Jon