Edward Snowden said in an interview that he chose to leak details about top secret programs to documentary filmaker Laura Poitras and reporter Glenn Greenwald because they had both been targeted by the NSA for being critical of the government after 9/11. The following are quotes from Snowden's interview.
Source: The Hill
“Laura and Glenn are among the few who reported fearlessly on controversial topics throughout this period, even in the face of withering personal criticism, and resulted in Laura specifically becoming targeted by the very programs involved in the recent disclosures".
“I was surprised to realize that there were people in news organizations who didn’t recognize any unencrypted message sent over the Internet is being delivered to every intelligence service in the world. In the wake of this year’s disclosures, it should be clear that unencrypted journalist-source communication is unforgivably reckless,”