Why should there be any "I can't vouch for the validity of it"? It's up on Michael Moore's website Put Away Your Hankies...a message from Michael Moore

I assume the idea isn't trying to "shame the voters" - it's a pep talk for people who are active in the campaign, but who might be feeling discouraged, because of the stuff they've been seeing in the media. Or have been taken in by the people who come across as attacking from the "left", but are working on an agenda crafted by the right.