The term Social Justice Warrior makes me want to throw chairs at people.
I first encountered the term as used by a friend who was attempting to motivate other anarchists and fellow-travelers to be cognizant of issues of accessibility at events within our shared circles. It was well meaning, but felt like something that I would've heard at a NVCD training in the anti-globalization years, in that there was what felt to me a naive assumption of shared goals.
Since then, I have only encountered it in internet trolling (and one time as obviously sexist irl trolling of a colleague, based on appearance) by people who are using it as a reaction against anything that threatens the status quo, or as a euphamism for "PC."
While the first example made me self consciously cringe, I also was able to contextualize it in terms of people with whom my affinities and differences were already known. The latter is merely a reactionary provocation. (I guess also from anarchists who are acting in reaction to identity politics, but at some point reactionary is just reactionary...)
To dig deeper, I am not a particular fan of social, nor do I feel drawn to most concepts of justice, and I hate anyone who labels themselves a warrior (unless we are talking about the street gang from Coney Island). As invective aimed at me by others I generally take it to mean that the person knows little enough about me and my perspective (and/or is too stupid to grasp my ideas) that they just throw out whatever inappropriate blanket insult they can find.