Oh no, I thought I had made that clear many times. Whether a song is "folk" to me implies no judgment about its merit. THere are some excellent modern songs, and some crap ones, and in 50 years the crap ones will have been forgotten. Most folk songs have have been filtered through the memories of generations and so the most forgettable have been forgotten already.

And no, there are quite a few contemporary songs that will often fool the casual listen and often be thought folk songs. Some would be

3 score and 10 (which I do)
Fiddlers Green
The gay fusilier (Pete Coe)(which I do)
Darcy Farrow (US, but still sounds US trad)
The importunate child (which I do)