The calculator hackers were putting their own OS on TI's hardware. Putting Linux on a Macintosh you have legally purchased is nowhere near the same thing as putting a copy of an OS (and an u-p-g-r-a-d-e copy at that) on your own hardware and then reselling it on a commercial level , for a healthy profit. Psystar knows damn well that upgrade versions of retail OS's are not eligible to be put on new machines.
Nobody would be surprised if Microsoft sued the pants of a company for hacking upgrade copies of Windows 7 to resell on their own machines. A Free market is not the same thing as a free for all. There are rules. If you want to play in Microsoft's sandbox you buy OEM copies. And just because Apple does not sell OEM copies does not give people the right to take the upgrade and do anything they want.
I was reading a story on a rather similar issue, Texas instruments calculator hackings who were trying to install a different operating on their calculator, and the article brought up Section 117 of the copyright law, which states:
'(a) Making of Additional Copy or Adaptation by Owner of Copy. ? Notwithstanding the provisions of section 106, it is not an infringement for the owner of a copy of a computer program to make or authorize the making of another copy or adaptation of that computer program provided:
(1) that such a new copy or adaptation is created as an essential step in the utilization of the computer program in conjunction with a machine and that it is used in no other manner, or
(2) that such new copy or adaptation is for archival purposes only and that all archival copies are destroyed in the event that continued possession of the computer program should cease to be rightful.'
So copyright law would seem to be to be pretty clearly on Psystar's side. You can legally modify software to run on different hardware, that is in the law.
Now it's only a matter of which the court gives importance to, Apple's EULA or written law. And I do not think a EULA is above the law.