If Plame was covert, her identity would be above Top Secret and on a need-to-know basis. Top Secret clearance is very common in the USG.
True enough but that doesn't change the argument.
The VP had a need to know since there were questions raised by Cheney about how Wilson (of all people) was selected for the Niger mission - a stupid thing for the CIA to do in any case but particularly so when they sent a liberal partisan hack and known enemy of the administration to do the job. Tenet was just responding to that issue in a meeting with Cheney.
You can make the same argument for the Cheney to Libby exchange. I'll stand by my position.