"Any arrangement or adaptation of the compositions in this book without the permission of the copyright owner is an infringement of copyright"

The quote I posted previously is taken from a Woody Guthrie songbook.

This land may be your land, but these songs distinctly ain't. No matter where Woody lifted them from.

Seems to me that singing a song written by someone else isn't nearly as serious as trying to prevent others from singing that song. Whether or not it's "adapted".

Any thoughts?