It's kind of "caveat emptor" in a way... ThinkSecret, being the "purchaser" (even though no money changes hands) is solely responsible to make sure that the information they receive and publish is coming from a respectable source and that said information was given to them in a legal and legitimate fashion.
Like buying a PowerBook from some schmoe on the street for a ridiculously low price. It's probably stolen, and it's the purchaser's responsibility to make sure that the goods are in fact good and legal, and if any question about the goods come up, the buyer should not buy. If he/she went ahead and purchased it, even though they didn't steal it themselves, they're still responsible for any consequences and in possession of stolen goods.
The fact that an NDA was broken makes that information tainted, and ThinkSecret has the responsibility to say, "Hey, we don't know where this came from or whether it's protected under some agreement, so I alone take full responsibility for any consequences for publishing it." The fact that the seller (or giver of information) wanted to remain anonymous should send up a red flag in ThinkSecret's head, and they should have refrained from publishing it.
He's getting exactly what he asked for. The action of knowingly publishing information that he knew (or even didn't know) was protected under an NDA put him in the "big boys" league. It's like a little-league baseball player getting a shot in the pros and expecting the pitcher to go easy on him. Gimme a break. The fact that ThinkSecret's editor is 19 years old, a college student, poor, rich or whatever has no bearing in this case at all. The fact that an NDA was broken and information was published by him is all that matters.
No more hiding behind mommy or the First Amendment (which, contrary to popular belief, is not the end-all be-all law of free speech and free press). There are many, many, many laws that supercede the First Amendment's rights -- such as contract law, which is completely applicable in this situation.
Even if your boss is truly smelly, do you think you'll be able to keep your job if you send emails to all your coworkers telling them how smelly he is? Even if you used your own home internet account? Even if you sent emails from your home internet account to their home internet accounts? Wait! I thought I had free speech!