I don’t know why they use this expression. It’s a text about “We Are the World” from an English textbook.
They recorded a song called “We Are the World 25 for Haiti” to aid people who were suffering from the disaster. As the title of the song shows, its roots date back 25 years.
Date back to is often found but date back isn’t, it seems to me. I did look up the expression in a dictionary. I found a lot more examples of “date back to.” The language textbook should prefer more-often-used expressions. But here date back is used. So I think that means the writer must have felt that “date back” is more appropriate here in the context. But I don’t know why. I want to know native speakers’ opinions. Is there any difference between date back and date back to? Is there any preference?
I’m waiting for you to “lend a helping hand.”