My guess is that Clinton was used to a large volume of correspondence and reports, most of which was classified at some level, and much of which was probably in the judgement of her staff and probably her self over-classified. When she hit a workflow snag, she made an executive decision to expedite the flow of stuff that in her assessment didn’t warrant the level of classification it had–efficiency over procedure. That isn’t technically her call to make, depending on the level of classification, and it sets bad precedent, especially when it’s something you order subordinates to do. It’s sloppy procedure and arguably bad judgement, though not at all unusual or particularly nefarious. And in all probability, the material we’re talking about as obscure, abstruse, and opaque, and of limited interest to anyone, though I don’t have any real idea of what the material was.
From my experience, now many decades old, of dealing with highly-classified stuff, there’s a certain lassitude that enters into your day to day interaction with such stuff day in and day out. You have to make a conscious effort to maintain standards and not insert your own judgement into the equation; if it’s marked “Top Secret/Qt3 Only,” you don’t second-guess that and treat it like it was just “Confidential.” It’s one reason why your security officer is usually nagging everyone all the time, because she or he knows that, left to their own devices, the highly intelligent and energetic specialists working with classified material will, eventually, start to make their own executive decisions, and that’s a Bad Thing in the greater scheme of it all. After all, the whole point of compartments is that most people will not and cannot have the whole picture in mind, and therefore have to trust the procedures to secure the information. Clinton, as State, probably had knowledge of a lot of the pieces, but even she can’t have knowledge of it all, by design, and certainly should not be setting that sort of example.
So, yeah, it’s a black mark in terms of how she operated in a fast and loose manner, at least in some instances, but whether that is that much different from how every single head of a department like State has always acted is another thing. As is, how much it bugs you. Given how most everyone in the government at a high level at some time or another has played fast and loose with classified material for political purposes, I’m a bit jaded these days.