Yes, but…

He was a definite hero in releasing what he discovered. He blew the whistle on things that the government was doing that it had no right to do, and that people had a right to know about. He risked his life and freedom to do it, and is paying for that by having to live in exile in Russia.

The “but” is that at times he has speculated on things that he doesn’t have any direct knowledge of.

For example, what he revealed in the PRISM leaks is that the US was tapping into submarine cables owned by companies like Google and getting the data that was going between various Google datacenters unencrypted.

That showed up in the PRISM leaks as this slide:

Snowden claimed that Google was cooperating with the NSA, when that slide shows what was really happening. The NSA learned how Google’s architecture worked, found a vulnerability, and exploited it without Google’s knowledge. Google reacted to the PRISM revelations by putting in a huge effort to encrypt data everywhere, in transit and at rest.

Until then they had thought that the data was safe. The places inside the Google network where the data was unencrypted were protected by significant physical security. They didn’t think anybody could get in, at least not get in undetected. But, their threat model didn’t include the US government treating them the way they’d treat an enemy country.

Google did “cooperate” with the US government, in that when it received a legal order for someone’s data they complied with that legal order. They even set up systems to make that process seamless. Things like the FISA court were a bit of a joke, so it was really easy for the government to come up with a legal order that Google release the data. But, Google still did require that the government go through the motions of getting a court to sign off on the orders. I think that’s why they were so surprised that the government didn’t think that was enough and had tapped into their backbone traffic.

If you look at what actual full cooperation with the government looks like, look at the revelations of Mark Klein. He was also a heroic whistleblower. What he showed was that AT&T set aside a special room in one of their facilities where AT&T would copy all the Internet traffic hitting their network so that the NSA could sift through it as they wished. There was no need for a diagram of where AT&T added or removed encryption because AT&T was just handing it to them unencrypted.

So, yeah. He is a hero for what he did. But, he was irresponsible for mixing the things he knew for a fact with his own personal speculation on them, because some of his speculations were wrong.