If you have, as you say, been visiting clubs for a while now then you should have known what it might be like prepared your friends accordingly. Seems to me this rant is about you being embarrassed in front of your friends.
Well, for me it certainly is. I would love the average folk club to be the sort of place one could take a friend and have them pleasantly surprised, even delighted, by what they found. But I have to confess that I'd rather stick pins in my scrotum than subject my friends to some of the dire stuff that one finds at the average club.
To generalise sweepingly, folk clubs are a bloody embarrassment. Every third person is someone you have to make excuses about, "Oh so-and-so's a great singer, so do forgive...," or "she used to be brilliant, but...", or "No, really, he's doing really well, given that..." It's like introducing a perfectly normal friend to a convention of train-spotters or any other slightly obsessive-compulsive and socially-inept hobbyists. You really don't want to do it.

Perhaps we have two parallel universes here - in one the clubs are all grand, every singer is pitch perfect and nowt's wrong with the world, and in the other one finds sort of clubs that Faye mentioned and that I've encountered. In my universe the folk clubs are going the way of the skiffle clubs, and - sad though it may be for those who actually like to sing and play - I think that's a good thing. There are too many talentless old bores who regard themselves as 'keepers of the holy flame of folk', and the sooner their cold dead hands are prized from the torch the better.