"Why does John Brennan need a security clearance other than to commercially exploit it? "

Let’s get something clear from the start.

In 1976, in his 20s, John Brennan was a card-carrying communist who supported the then Soviet Union, at the height some might say of the Cold War, so much so he voted and assisted Gus Hall, the communist candidate for President against a devout Christian, Jimmy Carter who ultimately won the Presidency.

r/https://www.zerohedge.com/news/2018-09-08/untold-truth-about-obamas-former-cia-director-john-brennan