Great debate! I go with George & Mike from Northumberland - allow the kids their mistakes, be entertained, as Old Folks always have been, by their mistakes and their pretentiousness*. While you're doing that, just guide them along.
There's a lot of crusty old opinion in this thread - understandable from those of us who know The Proper Way to Folk Sing maybe - but you have to take notice of the way music and media are changing, really you do.
In nature, things either evolve and grow or we only know them from ancient fossils. If you want something of "your" music to live on, you have to accept that.

*"leave home now while you still know EVERYthing"