I'd imagine it's because even before the SGSII was officially available stateside, it was still a known quantity and available from importers. Folks have had several months to froth at the mouth over this phone and now that they're finally here, they've got total tunnel vision.
I'd read that the Holiday would be a 4.5" where the Atrix 2 and SGSII are both 4.3". Not a big deal for some, but a huge deal for others. For me, as long as the device fits comfortably in my hands, I'm happy.
I'm thinking that the news will start to pick up on this one very soon, but that's purely assumption from me.
Atrix 2: Rooted, not yet ROM'd.