Well... yes, CDs are lossless, but to say they're representative of "full audio" is misleading. A single second in CD quality audio comprises 44,100 slices at 16-bits each. Real sound is not split into discrete parts - it's a continuous wave. With digital mediums, we have to cram as many discrete segments within a unit time as possible, but technically you are losing some data.
Where that poster is incorrect is that a 256kbps AAC is indistinguishable from CD quality audio. That is not the case. The differences are subtle, but they do exist. And while AAC can theoretically support 24-bit/96kHz audio, such files do not yet exist in the iTunes music store.
He is also incorrect in saying that vinyl is necessarily superior to CD. While vinyl is analog, the reality is that the amount of noise generated in the production and playback of analog materials creates a limit. My understanding is that realistically, they'd be about equivalent to 12-bit CDs. The "warmth" of the sound that many audiophiles claim to hear is likely due to the noise generated.