Why pick on guitar players in particular, when a bad banjo player can make as much of a nuisance as ten guitars?

Or is it just this feeling in Celtic sessions that guitars are somehow interlopers, especially if they do anything more than play straight chords, bang-bang-bang?

(Not that I'm denying that such guitar players exist, mind you. I've encountered enough of them. It's just that the original post was limited to guitars, and the problem isn't limited to guitars.)

P.