BGP attacks are largely defeated by onionservices.
And while governments have the ability to create exit nodes, so does anybody.
as far as i am aware, no one has been caught due to something technical in relation to tor.
it's always something dumb like logging into an email that has the person's real name in it, using a credit card, leaving javascript on, or otherwise making some opsec failure.
"Reading the criminal complaint, it seems that the FBI got itself a list of Harvard users that accessed the Tor network, and went through them one by one to find the one who sent the threat, [...]"
"The FBI didn't have to break Tor; they just used conventional police mechanisms to get Kim to confess," Schneier wrote. "Tor didn't break; Kim did.""
javascript, like tor, is powerful in both directions depending on what it's used for.