I think your definition of Terrorism must differ from mine Gordon
Glenn Greenwald is a
journalist. Would it be OK if I was held for 8 hours under terrorism legislation and questioned on where The InsidER gets some of his/her info? Miranda was not questioned about Terrorism once.
Presumably Mr Snowdon doesn't have first hand information on the surveillance of the Russian and Chinese governments, but from what he is saying (and he's not told everything he knows yet), the US government's programme seems a lot more advanced.
Mr Snowdon revealed what he knew because he was fed up of US officials flatly denying that they were running an illegal comprehensive electronic surveillance program against every US citizen (and everyone else who uses US based IT services such as Hotmail, Google etc).
Whatever your views on this, it's not terrorism.