For the most part, it appears these loud-mouthed few are from two camps. One is the paid shill prostituting his or her account for money, posting multiple dozens of messages each day for years 24/7/365. The others are suffering from an Authoritarian Personality. Erich Fromm said "the essence of the authoritarian personality is an inability: the inability to rely on one’s self, to be independent, to put it in other words: to endure freedom."
Members of the first group have no self respect, but may have the opportunity change into persons with ethics. Unfortunately, the second group, like others with an emotional or mental disability, are probably never going to be able to endure freedom, much less find joy in freedom.
There are, of course, those who have a genuine nuanced response of disliking Snowden and Greenwald while vigorously condemning this vile surveillance state. The key word, of course, being "genuine". Most of the people claiming a seat on that particular fence are, based on their overwhelming criticism of whistleblowers, lock-step support for an ideological leader, and vague muttering about civil liberties, are obviously from the second group.