Well, it pains me to have to say it, but of course it does depend on what you mean by folk music. Clearly, in this case it generally means, as has been pointed out, songs written by young white American songwriters. There are about a dozen songs in the list I would call folksongs. The rest of the list contains some remarkable songs as well, as you would expect. What you categorise them as is up to you, and it can neither enhance nor diminish the songs in any way, whatever you call them.