Considering a dropbox employee, corporate information, and internal security practices are on the line here: I think the author made the fair, ethical call.
That didn't happen. The employee account merely contained a list of email addresses.
RSA was hacked and the attackers could then get access to US military contractor internal data.
...
LinkedIn was hacked and the attackers could then get access to DropBox internal data.
Would the military contractors claim that they weren't hacked?
But making it sound as if Dropbox's security was compromised is misleading and inaccurate IMO.
If that weakest link happens to be an employee with a naive ideas about password security, it makes no difference.
This is the same silliness that makes people claim that social engineering isn't actually a security breach "oh they just phoned up the front desk and convinced them to be granted access, who would fall for that, that's not hacking!", yeah, no, someone just got 0wned.