This only says that their SMS tap at the carrier won't have visibility into messages sent over iMessage.

Even without iCloud backup, Apple, or anyone they add keys for on your account, can decrypt iMessages.

Apple's claim is specifically that they don't store those keys.

I agree with you...but to clear any confusion. What I'm implying is the same hypocrisy that Snowden is trying to thwart. By the gov releasing a PR statement (the one that I noted) as such, it instills confidence in iMessage, while the OP, you, and I have noted that there still are vulnerabilities.