SJ = abbreviation for "social justice."
The discussion here appears to be talking about "privilege" in a way that looks, from the outside of the conversation, like the use of the term "privilege" by both participants is based on attempting to reverse-engineer its theoretical structure from the way it's used online by social justice activists.
The idea of "privilege", as an academic notion within critical theories, does not boil down to "the thing that when you see it, you should call it out." Exploring and unpacking the idea may or may not come with exhortations to any particular course of action; this is especially so in the case of texts where the idea is being formulated, criticized, elaborated upon or revisited. That isn't even necessarily implied.
On the other hand it's very common to the use of the term by a certain subset of online activists, and it seems like for a lot of LWers group is their first or primary exposure to the idea. The result is akin to talking about socialism in general, by modelling it in terms of the Red Guard youth movement during China's Cultural Revolution.
Here was my attempt at a brief articulation, early in this conversation. I'm trying not to just reverse engineer from social justice blogging. But if I screwed things up, I'm open to suggestion.
I agree that privilege isn't inherently unjust. It just turns out that certain kinds of privilege are antithetical to my terminal values - and calling out appears to be the best response.
...On the other hand it's very common to the use of the term by a certain subset of online activists, and it seems like for a lot of LWers group is their first or primary exposur
As Multiheaded added, "Personal is Political" stuff like gender relations, etc also may belong here.