Is TOR compromised?

All the recent dark net arrests seem to be pretty vague on how the big bad was caught (except the IM admin's silly opsec errors) In the article they say he clicked on a honeypot link, but how was his ip or any other identifier identified, why didnt tor protect him.

Obviously this guy in question was a pedophile and an active danger, but recently in my country a state passed a law that can get you arrested if you post anything the government doesnt like, so these tools are important and need to be bulletproof.