Well that's a bit poor
But this does all come down to your definition of "capable," or "capable of running x." I'm willing to bet some of the crappy old machines I've got lying around would run Vista. They'd run it at a speed about that of permafrost movement, but they'd run it. So technically, they're Vista capable, right?
We've got some first-generation Vista machines around the office. Half a gig of RAM and Vista basic. They run it, but all I hear from their users is how slow the machines are, and how they randomly lock up for several minutes at a time. More RAM is on the way...