1. Person A hits Person B.
2. Person B hits Person A in return.
Is it ok that Person B hit Person A? I don’t know. I don’t think so. People would unanimously agree, however, that Person A making the first hit makes Person B’s hit more understandable, and that Person A is relatively more to blame here.
So, yeah, I agree: the attack from archivist isn’t justified by the attack from the journalist. It is, however, made more understandable by it.
As for what counts as attack: I think it’s a bit of a stretch to call DDoS to a blog an “attack”. It’s more like a protest. And I think the users of the service would in general not mind taking part in that effortless protest against the actor that is being hostile against the service’s continued operation.
Sadly, it backlashed quite a bit, it appears. People took the words “DDoS” and “botnet” as something much more serious than what they actually entail in this situation, probably because they sound very obscure and vile.