Scrubbed: All references to Frank Marshall Davis omitted from Obama's audio book

So Barack Obama's book, "Dreams from My Father" was first published in 1995. The audio book was released in 2005. The 1995 version referenced Frank Marshall Davis 22 times. The 2005 version had none. This is a very telling find from Paul Kengor.

Via The Blaze:

“Frank” — whose influence Kengor asserts was key to the fledgling politician and that the eccentric activist appears in “each mile-marker” of Obama’s path from Hawaii to the halls of Washington, D.C. — is mentioned no less than 22 times by name in “Dreams From My Father” and is referenced via pronouns numerous other times throughout the book.

But while listening to the audio version recently, Kengor noticed “Frank” had disappeared. He re-listened to the entire audio book on Tuesday afternoon and compared it to the unabridged memoir.

So what happened between 1995 - 2005?

It is also important to note that the audio version of “Dreams” was released in 2005, shortly after Obama’s now-infamous 2004 speech at the Democratic National Convention — a speech which made it fairly clear that the aspiring politician would indeed rise to prominence on the national stage one day. Back in 1994, when the original text version of “Dreams” was released, Obama was a relative “nobody,” hence his memoir, complete with references to a seemingly obscure character named “Frank” would hardly have been on the public’s radar.

To illustrate the blatancy of the omissions, here is one example of a before and after inclusion / deletion:

Original text version (1995):
“It was the same dilemma that old Frank had posed to me the year I left Hawaii.”
         
Audio version (2005):
“It was the same dilemma posed to me the year I left Hawaii.”

The common refrain of the Obama defenders ever since 2008, when it became known that "Frank" referred to Frank Marshall Davis and that the CPUSA member was a mentor to Obama, has been that Davis didn't have that much of an influence on Obama.

If so, why would all references to Davis be omitted in 2005?