If you jailbreak it and put it on a carrier other than AT&T, yes, you just stole a contract from them and cost them money.
If I jailbreak/unlock my unsubsidized iPhone that I bought secondhand from my friend, then I am not taking a contract away from AT&T (because I don't have one) nor am I taking money away from Apple (as they have already been paid)
And if you install a Hackintosh on a homebuilt PC then you just cost Apple the hardware cost they'd normally get from that sale, so yes again.
If I buy a copy of Leopard to install onto my PowerBook, then I have again already paid Apple for the hardware and have just paid them for the OS. They sell the OS separately, so don't tell me that just by buying the OS that a person is costing Apple a sale. And regardless of any other ethical or moral issues that you have, a great deal of people hackintosh because the $700 Mac Mini is not powerful enough, and the $1200 iMac has one too many screens for their existing hardware.
In my case, i was upgrading my desktop anyway, so I decided to give hackintoshing a try, and it is very nice to have just one computer that can boot both OSes, especially considering that my desk isn't big enough to fit an iMac and up until recently the Mac Mini wasn't exactly super-awesome.
But my pet peeve is really just that talk about both freely is just fine here, when I know the AT mods would lock any thread talking about pirated software torrents, no-cd cracks, etc which is a huge double-standard in my eyes.
Your point is valid in that the legality of Hackintoshing is a little vague, and most other legally dubious things are verboten on the forum, so the apparent double standard can be bothersome, but have you taken it up with Aphex, or the forum overlords?