Is this Apple clamping down on "hackintosh" computers, or just continuing to prune code that it doesn't need? The answer you prefer likely depends on your previous view of Apple.
If you think Apple is a company desperate to keep control over its operating system, you point to Psystar and the ongoing iTunes/Palm Pre compatibility battle, and this is just more wood for the fire. If you think that Psystar is nuts for thinking it has a case against Apple and think that Palm should hire its own programmers to sync its devices, then you're likely to say that Atom processors were never really supported in the first place, so it's all much ado about nothing.
Either way, I wouldn't expect the OSx86 community to pack up its bags and go home. I am sure that there are several folks already at work to find a workaround for this latest hurdle, and I won't be surprised when the announcement comes that they have a solution. The only real "blow" is to those folks who were previously able to install an unmodified version of OS X onto their netbooks. I was able to get 10.5.6 running on my Asus EEE 1000ha using my regular Leopard DVD and some additional drivers/kext files, but it broke again with 10.5.7 and I was never able to get it or 10.6 to work. I gave up and installed Windows 7 on it instead -- put down those pitchforks!
The removal of Atom support does not necessarily indicate anything about the fabled Mac "Tablet" since Apple could use the ARM processor instead. Or Apple could continue to say what they've said, which is (roughly speaking) that the iPhone/iPod touch is their netbook.
One thing is for sure; this move will do nothing to end any of these debates, but if you are using a netbook or other hackintosh, let me tell you what you've probably already learned: don't be too quick to install the latest operating system updates from Apple.