Back when the whole Snowden/NSA thing blew up, people talked about switch to TOR all the time to keep safe. The problem is, you kind of have to be disciplined and commit to it...and even if that's the case, you might be exposed by uncontrollable environmental variables. The apparent problem in this case was that the student was using Tor at the time of the incident...and I'm assuming he was one of the very few to have been using Tor at that time, and he didn't use it all the time...which makes his Tor usage at the time of the email stick out.

Obviously, he should've just not done it from Harvard's network (and obviously, he shouldn't have done it at all)...but I think it's a good lesson when teaching others about security...know the conceptual limits of the black box you choose to use.