No is not a folk singer because:

A. John Lennon was a real musician, he could actually write and play music that meant something

B. He would frequently write and perform using an acoustic guitar

C. His songs were frequently songs of protest or insightful observations about the conditions of life for the little people.

D. He did not wear the regulation uniform beloved by the little fellows who delight in regaling others with tales of having used the same toilet as Pete Seeger.

E. He would not have performed Michael Rowed the Boat Ashore at gunpoint

F. He never wrote any songs about working in a cereal factory during the summer when he was pursuing his degree in sociology.