This is silly.
The DNI takes an oath to keep state secrets a secret. He then takes an oath to tell the truth to Congress in an open session, which is itself an oxymoron when discussing a huge bulk of the national intelligence apparatus because we demand so much secrecy around every damn thing. How do you have an open session and not pretty much immediately invite some sort oath violation? It's the dumbest fucking thing in the first place but we like to play pretend to be open while simultaneously having metric f tons of state secrets.
There's a very long list of people who have appeared before Congress and lied under oath, and not referred for undeniable perjury charges. And they do not have the president of the United States giving them a defacto pass by saying Clapper was caught between a rock and a hard place. There is no f'n goddamn way Clapper was ever going to be charged with perjury. It's the dumbest line of logic, you need to go backwards in time to have this argument. It has nothing to do with Clapper. Go point a finger at people like Cheney and Feinstein if you want to whine about the massively neurotic security state.
And the idea you're going to find out jack shit about what's going on at CIA or NSA by charging Clapper with perjury is pure stupidity. If you want to know what happens at NSA and CIA, you need a society, in large numbers, who aren't paranoid and servile, and won't elect paranoid and servile representatives, who then accept the creation of a paranoid control freak surveillance state. We have what we have as a reflection of who we are, in particular those who do not participate. That's exactly how you get this kind of result.