I have, always, kind of wondered why "folkies" embrace some traditions and pay short shrift to others. While shape-note singing is, both, acceptable and worthwhile, barbersop quartet harmony is virtually ignored and trivialized. Bluegrass is in, polka bands are out. With banjos, it's 5 strings, good, and 4 strings, bad.
I think the choices are as political as they are generational. We tend to get into mindsets. I hated brussel sprouts and beets since I was a kid but, now, I, only, hate beets. (Winnie Winston loved brussel sprouts. He made me try them again).
I joined a barbershop chorus. It was the most fun I have had, singing. You guys ought to try it.
I started playing tenor banjo for jobs. A tenor is a great strolling instrument. It is festive, it can be heard, it is as defining as a costume. No one, ever, asks a tenor banjo player to play the latest rock hit.
I am not in a polka band, more's the pity. I am in a bluegrass trio and we do Pennsylvania Polka and Clarinet Polka, on request. They make great bluegrass numbers.

               Mike