BS, if they hosted the NYT and the NYT posted a leaked document, they wouldn't take them down. It all depends on power relations, perceived legitimacy, etc.; the only thing it has nothing to do with is their terms of service.
On the other hand, had WL not violated the AWS AUP, I also don't think Amazon would have taken them down, either.
The point is, if you don't violate the Amazon ToS, this is a non-issue (outside of personal politics, which is a fine reason not to do business with them, but a bit out of scope for this discussion.)
If the rest of the TOS is full of stuff like that, it would be doubtful it would even be possible to run a significant site without in some way violating the TOS. According to that TOS, one user-submitted comment of copyrighted content and your website could immediately be permanently pulled, even if you took the comment down as fast as humanly possible.
I think you'll find that you do.
You own that copy that you are presenting for distribution, no one else owns it nor has rights over it, you do (at least in copyright terms, PD could still have trademark and other issues).
The right to prevent other people copying it is exhausted, there is no [copy]right there to own so it's not a legal right that you don't have. That other people own other copies and have control of all the available rights to their copies is immaterial.
That said I think you're clutching at straws classified documents are not in the public domain unless they have been published by someone with the right to do so and the copyright term in the relevant jurisdiction has expired.
There are about 30 states IIRC that aren't signatories to Berne Convention or relevant parts of TRIPS, etc..
Does that sound credible to you? Does that seem like a reasonable comparison? I'm done arguing about WL on a thread about a new Amazon web service now.
At any rate, I'd amend your "if you don't violate the ToS" to "if you don't attract a phone call from a cranky old senator's office", since that's what seems to have prompted the action.
Try taking the words at their face value, instead. The motivation is avoiding another 20-comment thread that spends 70% of its time dancing around the subtext of one commenter liking WL and the other commenter not liking WL.
Try what Wikipedia tries to do: Assume Good Faith. There are people on HN I, too, have a hard time doing that with, so if you're not assuming good faith because of a 'tptacek issue, please feel free to email me about it.
By this standard, I fully expect AWS to terminate services to EVERY SINGLE forum, review site, message board, webmail service, and any other site that does not explicitly state in their own terms of service that every byte of user-generated content is the exclusive property of the site itself.
In addition, I expect any AWS customer hosting IETF RFCs, software with public domain licenses, and public domain poetry to be shut down immediately.
If AWS fails to do this, they are being discriminatory and capricious in pursuing TOS violations.
If I were to be cynical, I'd say that the purpose of that clause is to allow Amazon to take down any site they want and have a credible excuse. Realistically it's probably just some over-zealous lawyer, but either way it has that very effect (as Amazon has demonstrated).