It's pretty well-established -- Snowden
stressed that he "carefully evaluated" each document he leaked to both make sure it was actually in the public interest and that it wouldn't hurt others. Yeah, it's his version of events, but in hindsight I don't think we've ever seen him leak something he knew would compromise someone's safety, and he's been a thoughtful (though not flawless) commentator in the years since.
Let's put it this way: he's definitely not a Julian Assange type who thinks raw data dumps are a substitute for journalism.