Well I am a 100% folkie, and I love oldtime music. But I am a Brit folkie, and I suspect the implication of the word may be radically different in America. To my way of thinking, oldtime(in this context) means "American folk music", so it would be funny to be a folkie and not like folk music. But I believe "folkie" in this American context carries implications of "liker of modern singer songwriters", and obviously someone in that category might not like oldtime.