Because he’s using non-violent direct action, and not merely blowing the whistle in the traditional sense.
What’s the difference?
Traditional whistleblowers raise concerns internally–to an Inspector General, to one’s boss, to Congress–and only then do they go to the media. Their identities get exposed, their lives come under scrutiny for a few days or weeks, and then they’re left to fend for themselves in court while the rest of us have moved on. If they followed the rules so far, the issue gets aired, debated, and then forgotten. The public shows somewhat-abstract concern, but most of us don’t have a dog in the fight, if only once the issue gets resolved at some level or the whistleblower moves past the crisis stage.
Snowden, by contrast, is using a different playbook. If you despise how he blew the whistle but condemn what the government is doing, you’re probably going through cognitive dissonance that you’ll have to resolve. If you don’t mind (or you admire) how he blew the whistle and condemn what the government is doing, you feel inclined to defend him to others. If you hate what he did and you support the government’s actions, you’re inclined to defend the government to others.
In others words, you have to pick a side. There are no bystanders here.
There’s a name for this kind of strategy: creative tension.
Photo by Fibonacci Blue released under a Creative Commons license.