I actually like the paper analogy a lot, let's extend it: Say the journalist was instead freely handed a redacted government document on sheets of paper. The reporter notes that it was redacted poorly and the redacting can be peeled off or a bright light can be shined on it to reveal the text underneath. By doing this, is the reporter committing a crime? I have no idea. My intuition says probably not, but I think interestingly it's not a "definitely not" because 1) it's apparent to the reporter that the redacted information is intended to be private and 2) the reporter took some steps to uncover that information.

It's still not a perfect metaphor. It's not immediately clear that 1) is true here (the reporter probably was not trolling for private information) and it's highly questionable if 2) is true as it seems that this info was being sent along in HTTP responses. What is obvious to me is that that this guy had no malicious intent, took steps to do responsible disclosure (they didn't publish the article until the issue was fixed) and is being targeted by the political establishment as retribution for embarrassing them. Shameful stuff.