I don't know why the punch up starts as soon as someone says what "folk music" means to himself or herself. I can't get worked up enough about it to start spitting bile at everyone, who has a different opinion to me. I think there is a good chance that the most enduring of twentieth century pop music will end up as folk songs. Just what the "folk process" is these days will need a bit of distance to define. We have experienced barely a century of being able to accurately record performances of music, so the future folk process looks likely to take a different form, to the one which was described in the nineteenth century.
To me John Lennon was a very entertaining rock singer, who was about a century short of becoming a folk singer. However, I can't get passionate enough about defending my definition that I want to start hurling abuse at anyone. Why is it so important that everyone else is wrong?