All right, parasitic was at the end of the range you referred to. But you still said it.
I simply don't understand your reasoning. Or unpleasantness. Which aspect of musicians (and possibly other artists) attending a festival and doing their own thing when they're not actually at the organised bits, do you find so abhorrent? Most places that host festivals have - let's call them 'venues' - that are only too happy to host informal gatherings, or even engage professionals to encourage them. Severed head said "it really needed an informal singers and musicians session", and has pointed to a suitable venue. So where do you see a problem?
Nobody has suggested running an alternative event.
Even the street people that invariably accompany festivals add to the ambience and festive spirit (not sure about amplified pan-pipers!)

I hope you have a pleasant day elsewhere, and that no folk musicians turn up to spoil you enjoyment.