Officially, historical revisionism is pretty much the core of historical research. As you said, readjusting our interpretation of historical text and so on is the natural way to get to our desired result. And if you ask a historian, they'll definitely differentiate between the popular usage of historical revisionism - where it's used derisively - and the academic version.

I find that it's hard to maintain this official version, however, because historians themselves are guilty of often using the term to deride works they don't agree with or are opposed to for other reasons. It essentially comes down to how we present our opinions through language, even if we do so in a roundabout and perhaps subconscious way. When we come across some new research, if we agree with it or at least attach a certain value to it, we'll be much more likely to talk about "new research says..." or "the latest research" - we're showing our acceptance of the research by playing into the general notion that newer equals better. We're attaching a positive qualifier to it.

When we come across new research we don't agree with or find flawed in some other way, however, we'll be much more likely to resort to the more neutral "historical revisionism" - so while we're not explicitly saying it's bad, we're not saying it's good either. Add to this the fact that because historical revisionism is such a basic part of historiography, it's rarely actually mentioned outright - so we can tell that if someone does mention it, he's doing so knowingly and with a certain purpose.

This all contributes, in my opinion, to the negative connotation the term carries to the point where it's impossible to just stubbornly maintain that it's just a neutral term for an essential part of the historiographical method. It's still worthwhile to point out the neutral meaning, however, because many important and valid historiographical movements and historians have been called revisionist without there being an intended negative connotation.

If we look at the issue through a more postmodern lens, however, the line between the popular and the academic version of historical revisionism begins to blur. Specifically, the idea that ideology plays a part in the "revisioning" of the past - because as we revisit old sources or old research, we do so in a different political, societal and ideological context, meaning that all forms of historical revisionism are essentially influenced by contemporary ideology in some way or another. This makes it much more difficult to explain the difference in value of, for instance, the historical revisionism that moved away from the way various colonisation projects were described as ways to bring enlightenment or fight slavery and the historical revisionism of someone like Niall Ferguson when he writes his garbage thoughts on the British Empire.

To explain the difference in value, you'd have to either enter a political debate (which most historians aren't very keen to do) or go after the methodological mistakes (selection of sources/events being a key one) that someone like Ferguson is bound to make in order to reach his bad idiot conclusions. That's rather difficult to do for a layman, alas, which is why the classical interpretation of historical revisionism is still the most popular.

PS: This was actually the subject of my first historiographical paper, back when I was still in high school. My thoughts on the subject have evolved significantly since then (there's been some heavy historical revisionism), but it really takes me back.

I'd also like to apologise if the post's a bit rambly. I tend to add stuff as I think of them and that's not the best way to deal with structure.