The point is: when the vampire is exhibiting weakness you drive a stake through its heart. The vampire turned a bunch of your fellow townspeople into vampires; saying the bite is no longer so bad doesn't mean that the vampire is now to be respected.
It's also not about punishing Microsoft. [Sure, the warm glow of schadenfreude feels nice.] It is about demonstrating to the tech community the long term costs of SHITTING IN OUR SANDBOX. Those of us who were developing web sites during the IE6 days want to show Google, Facebook, Apple, Zynga, Adobe, etc what happens when you Embrace and Extend web standards.
You don't know frustration until you get your website all sorted in FF 2, then open up IE 6 only to see a completely jacked website, only to realize you basically have no web development tools for IE 6 and you'll be spending the next 2 days blibdly fiddling with margins, padding, how-to-force-zoom, etc.