MoveOn.org's backup policy
Based on the file name (www.moveon.org/images/
FKbxnT3hzaHCcOR7vWvRYmZpbGUtMTM4OQ--.mpg) I believe I can come up with a logical explanation.
Obviously, this was just a backup copy. Sure, it's extremely foolhardy to leave your backups online, but - obviously - the kind, gentle folk at MoveOn were a bit distracted in their righteous fight against $hrubCo, his NeoCon handlers, and the Christian Taliban.
Some might point to the fact that moveon.org/images is a forbidden directory, meaning its contents cannot be read by surfers, and say that this link was distributed by MoveOn or its members in some way. How else could Mr. "Sludge" have found out about it?
I will leave speculation about the source for his link elsewhere, suffice it to say the VRWC moves in mysterious ways: "RNC Chairman Statement on Hitler Ad on MoveOn.org Website."