Don't bother.
While this document is an exaggeration, the Snopes site is equally bad.
Snopes claims none of this document is true, but in fact many of the signers did suffer harm due to their support for the CAUSE of Indpeendence. Snopes plays a subtle word switch by saying that none of the, suffered harm for signing the document. True enough: the British didn't care anything beyond that they captured enemy combattants. That was enough. But the fact is that many were captured, killed, impoverished or mortally sickened by living up to the OATH contained in the document.
Please, people: Snopes is hard-core leftism. Do not refer people to it!
That's a matter of opinion, but I'll forego arguing it. I think the point you concede is one that's important: those who signed the Declaration of Independence were remarkable men in the final analysis; they don't need a glurge fiction to make them any more noble. When such fictions are allowed to stand, they only denigrate the character of the real people who founded this nation.
Maybe sometimes, but not all the time. See http://www.snopes.com/glurge/birdwell.htm.
Hell, snopes is more balanced than CBS, the NY Times and/or the LA Times or any other major media outlet.