here, there's a subtext that Tor actually made NSA's job easier
Are you reading anything from that subtext beyond, "Tor has a high concentration of the kind of users we're interested in, so let's keep it a juicy target rather than squeezing too hard?"
As I understand it, which admittedly isn't well, it made surveillance jobs easier when its users mistook anonymity and privacy. That is, sending something through the tor network means that it's more likely that your traffic is going through a node belonging to a group that records everything than if your traffic randomly found a point to point route across the internet.
I don't see how using the Tor network could make you less anonymous, unless as you point out, it's use suggests a user's greater likelihood of sending and receiving interesting information.
It hurts the system that exit nodes have been targeted for content that other users were responsible, but from how I have read, Tor can provide people meaningful anonymity that is difficult breach.
As an aside: What is the effect of such parenthetical statements? I think they just create a vague idea of uncertainty and fear. If there is a vulnerability, there has to be a mechanism, not just a sense of omnipotent government surveillance.
Maybe that mechanism is the probabilistic likelihood of an organization controlling a large portion of the Tor nodes' ability to identify users. Maybe it's a flaw that has been surreptitiously put into the source code. I'm pretty sure more people who know would suspect the former as far more likely than the latter. It's easier to address the questions when you know what the parenthetical utterance was even referring to in the first place.
Side note: no intermediate node in the Tor network can see your traffic in clear. They just see the encrypted data. The only node that could see what are you sending is the exit node, but that can be solved easily using HTTPS.
I don't know that it really is subtext here, but I suspect that Tor has many people communicating electronically where they would otherwise refuse to do so at all. In other words, "Normally I would refuse to talk about this on the internet and would meet you in the back of the bar instead, but I trust Tor so let's discuss this now."
It therefore puts communications that previously would not have been available to the NSA into the realm of things that the NSA can access.
Are you reading anything from that subtext beyond, "Tor has a high concentration of the kind of users we're interested in, so let's keep it a juicy target rather than squeezing too hard?"