The songs in these books are varied. Hundreds have been used over the years. I could open any one of them and find a song that could be considered offensive -- by someone looking for trouble.
As a conservationist I shudder when I remember the song "Our Fathers Cleared the Bush". Of course that would be considered, by some, to be the way to go. There are objections, here in this corner of Aus.-- fairly often to what is called "green brainwashing" in schools.
Among the songs in these books, during the 70s, there were ones by Dylan and by the Beatles that could be taken apart and misread.
I learned "You're Always Welcome at our House" (Shel Silverstein) from one of them. Children love that song, and rightly, but it could be seen as avocating violence -- I stress again by someone looking for trouble.
It's interesting that there have been no objections about the content of these books before now. It's a sad day that there is now.
Cheers, Joy