It would be the same thing if Apple sold music with DRM removed without permission of the record labels. Apple doesn't do that.
When you compare this with Psystar, in each case we have a company (or companies) that wants to license their product in a certain way, with another company not quite happy about it. Psystar did go ahead and use the product without license, Apple didn't. The real question, often missed in the Psystar threads, is: Is it anti-competitive? Is it preventing a company from competing?
In the case between Apple and record labels, I am not sure, but Apple isn't suing anyone, so it seems to be Ok. I think an important factor is that the iPod is so strong in the market, and it could be argued that both Apple and Amazon have a license that allows the music to be played in iTunes, on an iPod, and to be copied to an audio CD, and the DRM only prevents the end user from doing things that are illegal anyway.