As a founding board member of two of those three organizations, and former board member of the third, I guess I should be proud that a 96 year old organization would be so terrified of our work. And I would be -- if there were anything in this fundraising pitch that was actually true.
But there is not. Creative Commons, Public Knowledge and EFF are not aiming to "undermine" copyright; they are not spreading the word that "music should be free"; and there is certainly not yet any rally within Congress in favor of any of the issues that these groups do push.
I know Creative Commons best, so let me address ASCAP's charges as they apply to it.
Creative Commons is a nonprofit that provides copyright licenses pro bono to artists and creators so that they can offer their creative work with the freedom they intend it to carry. (Think not "All Rights Reserved" but "Some Rights Reserved.") Using these licenses, a musician might allow his music to be used for noncommercial purposes (by kids making a video, for example, or for sharing among friends), so long as attribution to the artist is kept. Or an academic might permit her work to be shared for whatever purpose, again, so long as attribution is maintained. Or a collaborative project such as a wiki might guarantee that the collective work of the thousands who have built the wiki remains free for everyone forever. Hundreds of millions of digital objects -- from music to video to photographs to architectural designs to scientific journals to teachers lesson plans to books and to blogs -- have been licensed in this way, and by an extraordinarily diverse range of creators or rights holders -- including Nine Inch Nails, Beastie Boys, Youssou N'Dour, Curt Smith, David Byrne, Radiohead, Jonathan Coulton, Kristin Hersh, and Snoop Dogg, as well as Wikipedia and the White House.
These licenses are, obviously, copyright licenses. They depend upon a firm and reliable system of copyright for them to work. Thus CC could have no interest in "undermining" the very system the licenses depend upon -- copyright. Indeed, to the contrary, CC only aims to strengthen the objectives of copyright, by giving the creators a simpler way to exercise their rights.