"Illegal" and "wrong" are not in any way related. All spy agencies conduct activities which are clearly illegal under the laws of their target countries. But are these activities always "wrong?" Conversely, spy agencies may conduct activities which are legal under their own laws, but are morally wrong -- harassment of MLK, for example.
And "unambiguously legal" is overselling the point: PPD-20 includes offensive capabilities amounting to acts of war -- which would presumably be illegal absent congressional approval. China surveillance includes illegal surveillance of US nationals and well as mass surveillance, which is arguably inappropriate policy. Tempora is a program conducted by the UK -- arguably illegal as signatory to EU treaty. Spying on Germany is likely to support economic espionage, which would be illegal under WTO treaty, etc. Al Jezeera is a journalist organization, which provides a useful Arab propaganda counterpoint to US propaganda, and is not itself a sponsor or advocate of terrorism. The various spying methods exposed are executive overviews and lack sufficient technical detail for implementation, and are thus appropriate for public policy discussion.
The US state security apparatus is also not elected -- yet it clearly does control policy through overclassification and outright misrepresentation of its activities to congressional oversight.
Were Mr. Snowden's actions illegal? Yes, clearly, but that is a question of no meaningful value in this context, as most NSA activity is illegal somewhere, and some NSA and FBI activity is clearly illegal within the US.
Were these actions wrong? That remains to be seen.
Even if they were wrong, is there a net moral benefit which could excuse the costs? That is a complicated question. Do the fruits of NSA, CIA and FBI espionage achieve their stated goals? Is US foreign policy successful? Does the US reliably achieve its military objectives?
So, rather than yet again repeating the mistakes made over the last 100 years -- with some exceptions, an otherwise disgraceful litany of paranoia and short-sighted pragmatism -- perhaps it is a good time to reexamine politically whether foreign policy as practiced by the US is appropriate and efficacious. The responsibility for this interminable chain of dismal failures must be accepted by the US government and US electorate as a whole. The status quo -- mindless subservience to nationalism, patriotism, and religion along with a generous dose of political amnesia -- is completely unjustified at this point.
This discussion cannot ever fully occur when the mechanisms informing that foreign policy are forever hidden from political debate by a veil of overclassification motivated by criminal activity.
Mr. Snowden has caused that debate to begin -- his stated intent. One could therefore reasonably conclude his actions are moral and justified as well as illegal under US law. US law is therefore the problem, not Mr. Snowden.