You're right of course. Unfortunately--and astonishingly--the vast majority here seem to think otherwise.
Personally, if someone buys a copy of Leopard, I'm not sure I consider it immoral to load it on some other hardware. Legal or not, that is another story.
However, I completely respect the right of Apple to throw as many monkey wrenches in the process as possible. I would consider it completely immoral for the court to say something like, "Apple must facilitate interoperability with OS X running on third party hardware."
Part of the OS X experience is running on a limited set of known hardware. I'm not sure why people don't get this. Otherwise, your best bet is you end up with something like Windows. When done poorly, you end up with the Linux distros of the 90's and even today to some extent. What is wrong with having a best of breed OS that isn't plagued by having to support every half-as_ed chipset coming out of China?
Sadly, the benchmark for whether hardware "works" and can be shipped is whether it works with Windows. This has plagued Linux for years. Crap hardware gets produced that doesn't even adhere to industry specifications, but the combo of crap hardware + windows + a crap driver halfway works, some of the time. But try to plug it into Linux and it won't work because it doesn't adhere to the specs. In the same fashion, a lot of broken HTML is largely considered valid because it runs in IE. And worse, Firefox and Safari end up supporting broken stuff because there is so much of it out there.
Anyway, I'm sure at some point someone is going to sue Apple and I wouldn't be half surprised if the court orders them to start supporting installations on 3rd party hardware. People have went after Microsoft for years, and if you think it has to do with anything other than the fact that Microsoft is a big company and a big target, then you're crazy. Apple will become just as big of a target. All these lawsuits do is cost the company money which results in exactly two things- increased costs for consumers and increased money in the pockets of lawyers.