At the risk of sounding repetitive and incurring all kinds of discussion if not down-right emnity depending on the level of passion involved I repeat:

A traditional folksong is one which has variations (variants)and has accumulated these over a period of time from having been sung by many people. It usually is associated with a cultural sub-group or community. Sometimes the original author can be found but the song has changed. IE: Angelina Baker by Stephen Collins Foster becomes Angeline the Baker and a fiddle dance tune. Maud Irvings "Wildwood Flower" is morphed by the Carter Family and takes on a different life of it's own. It might be a quasi-folksong. Barbara Allen was all but forgotten until it emerged in print and became active againin the folk process.

You don't write a folk song. It becomes one through having been sung and changed through the years. You can however write a folk-style song which Alan Lomax has referred to as an "art song". Was Woody a folksinger? Yes and no. Yes in a way because he brought to his writing a style that was consistent from his background from Oklahoma and messed with trad material such as the Buffalo Skinners to participate in the process. No, in that he composed specific songs in a folklike style. Both he and Jean Ritchie brought to their compositions a sense of integrity and cultural continuity because of their respective backgrounds which means that when they composed music in a folk-style it has the ring of authenticity to it.
Technically, as great as those songs are, they haven't stood the test of time to make them folksongs as of yet. In a hundred years maybe someone will collect variants of them and they will have become folk songs.

This should stir up a response.

Frank Hamilton