That generated more response than I expected. I actually
do agree that, on balance, it's somewhat more likely that it's just a benign glitch; I should have said that. What I was really taking issue with is the dismissiveness with you treated the suggestion that this might be an NSA attack. I was responding to what I saw as a slanted and unreasonable framing by doing the same thing from the other end.
So with less snark: I don't think it's exceedingly improbable at all, and whether ultimately it turns out to be the case or not, smugly guffawing the idea that the NSA may have used a trick like that isn't warranted. They really do intercept people's laptop shipments [1] to plant malware in them. They really do sneak tiny radio transmitters into end-user hardware. They really are trying to get backdoors into communication tools. I'll put it this way: if I worked on the kind of software Andrea works on, I would be seriously alarmed. Would you keep the keyboard?
On some specific points you made:
* That Snowden had access to other people's credentials seems like a serious operational shortcoming to me. The "low-level" part wasn't an attack on Snowden; the point is that a lot of people have that level of access. In general, the US intelligence apparatus makes a lot of well-publicized mistakes; I'm sure they make a great number of more subtle ones.
* On the NSA's shortcomings generally, I think this is actually nicely illustrative. Because a lot of the stuff Snowden revealed were things a lot of credible people already believed, based on things like weird locked server closets in telecom buildings and PRNGs that seemed fishy and pointless and heresay reports of requests for backdoor access to communication tools and so on. There was just little hard evidence before Snowden. And there won't be here either. So this is entirely consistent with the what the NSA was like in those decades where their programs "never saw the light of day".
* I think being a core Tor developer makes her high value target. It's hard to imagine the NSA wanting to subvert all the things it's subverted and not wanting to backdoor Tor. Keylogging her keyboard is a great way to do that, either by compromising her somehow, or by just stealing her credentials. So I don't follow the "it doesn't make any sense" line of thinking.
* That she's now tweeted about certainly makes it unlikely that, if the NSA has it, they'll go through with sending it bugged. But so?
Where I come out on this is that yes, it's probably nothing, but it should be treated with suspicion and carefulness, not laughed off because haha, what, do you think you're in a spy movie or something? Because, basically, we are.
[1] Yes, I know this is just the keyboard. I don't think that's a relevant difference.