I always, for saome reason, associate Barber Shop singing with those people who yearn for a forgotten (and imaginary) time when the world was perfect. It's all Edwardian gents with centre-parted hair and handle bar moustaches, and it's all very fake indeed.
I also associate it (and this is for British readers only) with the radio show 'Sing Something Simple', the most depressing programme in the history of broadcasting.