Folk (in England at least) has suffered from a poor image since the second revival (1960s) mainly through the media portrayal of Folkies. Earlier attempts to put Folk under the microscope and make it academic also contributed to the public perception of minority weirdness.
Folk: Often synonymous with tradition but commonly meaning 'of the people'. Which often means 'of the common, usually working people' as it's songs are full of trades, crafts, human dramas and the aristocracy when they appear are often the villains. The word folk derives from Old English for people, men, tribe and has a commonality in most Germanic and Norse languages (volk). There is therefore a sense of proximity to the Stories and Sagas which the romance languages and countries do not possess.
There is a strong anti-establishment feel generally to the folk tradition (e.g. the smugglers outwit the Excise men) and there is also a strong element of protest, suffering and oppression but there is also love, humour and pleasure. Much of the folk tradition is about social gatherings and music and dance, often associated with times of the year such as Harvest, Wakes Week, May Day etc. and human attributes, actions and pastimes such as courting, murder, marriage, gambling etc. A lot of folk memory has been lost, contributing to the weirdness factor in folk. What was a common experience for almost all people up to the 1850s has been erased in less than a century so that not a vestige of the culture remains in some areas - indeed it is now scoffed at or mocked. To compound the evil, themed 'Merrie England' has been introduced into pubs and shops so that Folk is now mixed by association with marketing and the deep suspicion that brings.
Folk is regional and national. Actually more ethnic, racial or tribal than geographical or political. Tunes, Songs and Dances are seen and heard in different forms but which are nonetheless recognisably similar and have common ancestry not only in regions of one country, but in different countries. By contrast, some regions have peculiar Traditions, songs, tunes, dances or instruments which are unique and found nowhere else.
Folk is an Oral Tradition. It is meant to be passed on by repetition and word of mouth and not captured in writing. There is no definitive version of anything in folk music - that's the point.
Folk is not living in the past although nostalgia plays a big part in some of the songs. It a canon of work which bears repeating. It evolves and is added to by contemporary artists.