Ron Davies says it all for me so I won't repeat it here. I don't mind listening to "bad" or beginner singers singing songs I personally think are trash, thats part of the folk club tradition, but if a song's worth singing its worth making the effort to learn the words and having done that and lived with the song awhile maybe you can put some feeling into it which in my book can make up for a lot of "bad" singing.
BTW went to a couple of Sac. song circles some years ago-too cultish by half for me!