In the same way that not all 'scientists' agree that evolution explains all life on this planet.

lol.

P.S. The article is ancient news. MS backed down from their original plan to make IE8 default rendering of 'IE7 aka broken' after a shit storm from the web dev community. It got nasty. Zeldman, in particular, came out of it badly bruised as he bizarrely supported MS's original idiotic plan. It's now going to default to 'the best we can do' - which should mean ACID2 is passed. Like I said, this all happened months ago.