1. Sheryl Crow

2. Bruce Springsteen

3. Martin Sheen

4. Ed Asner

5. Sean Penn

6. Tim Robbins

7. George Clooney

8. Jackson Browne

9. Janeane Garofalo

10. Neil Young

11. Jessica Lange

12. Barbra Streisand

13. Danny Glover

14. Susan Sarandon

The only explanation for their continued silence must be a large, organized kidnapping. To whoever is responsible for their disappearance, please post pictures of them holding a recent newspaper so we know they're okay. Maybe one of these:

Update:
After this article was posted, Ed Asner was apparently released and spoke with the Hollywood Reporter. In it, he says celebrities are scared of being labeled "anti-black" by opposing the war. He must have still been a little disoriented from his incarceration and meant "scared of being kidnapped".
Danny Glover, as well, was able to heroically escape his captors long enough to fill out an online petition urging Congress to oppose the war. Unfortunately, we believe he was re-kidnapped before he could make any forceful appeals to the president.
Other celebrities are still "unavailable for comment", which we believe is lawyer-speak for "held somewhere against their will".
Yours in continued peace,
America