The poll, while shameful, is probably correct.
Obama has been very weak in his support of whistleblowers across the board. He has hunted down and prosecuted more than any former President (http://www.theguardian.com/us-news/2015/mar/16/whistleblowers-double-standard-obama-david-petraeus-chelsea-manning)
With no major political figure left who supports disclosure of illegal government activity, it is not surprising that the people don't support it.
The US is behaving like a state with a bunker mentality rather than a global superpower.
A sure sign of its decline.