Far from it, plenty of staunchly liberal people use the acronym SJW. Getting riled up by the term is analogous to people on the right objecting to "white privilege" and complain that it's categorically dismissing white people's opinions.
The bigger irony is that your comment claims that the term is used to categorically dismiss people, while simultaneously categorically dismissing the above poster's commeent.
You may have, but I've never met such a person, and that's a false equivalence. And it is not really ironic; when you use an inflammatory term especially in a headline, you use it knowing what the term evokes and it's a clear sign of what kind of audience you're pandering to. And I will judge that person accordingly. That said, considering the post came out in 2015 (which I didn't know at the time of making that comment), I think it had not yet totally become a blanket term synonymous with "liberals" so I can mostly reserve judgement in this case. Again, though, i don't think this is really all that relevant to the topic of stallman.
The bigger irony is that your comment claims that the term is used to categorically dismiss people, while simultaneously categorically dismissing the above poster's commeent.