My problem is that I should be able to install software on two computers that I own and I am the sole user of. I don't care if the price to do this is reasonable or not; there should be no price difference between this and buying it for one computer.
I know the CD analogy is somewhat flawed, but I can play a CD in the CD player in my room, or the one in my car, or somewhere else. Software should not be tied to hardware, it should be tied to people (if tied to anything).
You are allowed to do this. Simply uninstall the software from the machine you are not using it on. Just because you think you should be able to use it does not make it your right to use it. Having said that, I am sure Apple knows that people will do this to a reasonable degree and that is why, to date, they haven't used any sort of activation method.
The problem with the CD analogy is that you are not installing anything with a CD or DVD. With software you are actually making a copy of the disk contents onto your hard drive. It is that action that the license agreement "prohibits" you from doing more than once at any one time.