dxu, would you care to weigh in?

Sure. What I meant was that presumably, "attacks" are considered damaging for a reason--namely, that they make discussion more unpleasant. This "unpleasantness", however, is a subjective matter, and whether a particular remark generates an unpleasant feeling is entirely up to (the brain of) the "target", as it were. So I suppose my reply to Lumifer would be something along the lines of

Nope, sorry, I don't buy the "a victim is always right about being a victim" approach.

If we're talking about effects on the victim ("victim" is not the word I would have used, by the way), as a matter of causal fact, then yes, in fact, it is. You could try to argue, of course, that the "victim" overreacted and shouldn't have felt attacked by that remark, but the fact of the matter is that he/she did in fact feel attacked.

Of course, just because someone feels attacked doesn't mean you did something wrong when addressing them--it's entirely possible, for example, that the person in question really is overly sensitive, and that a large fraction of people would not have taken umbrage to your remark. This possibility grows markedly less likely, however, when several users independently claim to find a particular poster's comments unpleasant as a whole.

I should also point out that comments, especially long comments, take some effort to write. When confronted with such a comment, I've noticed that Lumifer generally does not address the entirety of the comment, instead selectively quoting several sentences from various points in the comment and then snarking at those. When someone does this, it feels (at least to me) as if they're not actually taking the other poster seriously; if I put a lot of effort into a post and write several paragraphs for you to read and then your reply consists of one-liner responses that are more condescending than informative, it feels as though the effort I'm putting into the discussion is not being reciprocated, which makes me less likely to continue the discussion.

EDIT: An example of the above would be Lumifer's reply to your (gjm's) comment, which simply reads:

The options I had, writing that sentence

That's good evidence that your sentence has problems :-)

Snarky one-liner? Check. Does not actually address the main point? Check. More condescending than informative? Check. This is exactly the sort of thing I'm talking about, and it was found in the immediate next comment in the chain. You don't even have to look for this sort of thing from Lumifer; that's how often it happens.