My arguement is that, do not just slap 'Social Justice' over them, what they are doing isn't fighting for actual Social Justice.
No stuff sherlock, we don't call them "social justice warriors" because they're in the right.
It's normally used for people who either:
a. take stuff way too seriously
b. are narcissistic to the point where they think they're the center of everything and that everyone else is required to put up with their bullstuff (some examples are weird-ass completely unnecessary genders like "xem" or "hesh" or "zie," (there are literally hundreds of these. Nobody needs to remember this stuff.) being morbidly obese and expecting
everyone to think they're beautiful while they do nothing about it, dismissing an argument from anyone whose white, straight, or both because they're "privileged," the list goes on)
or c. try to get justice for things where there is no injustice in the first place ("a male beating a woman at a fighting game and saying "it'll all be over soon" is rape!!" once said a social justice warrior.)
Though the definition varies from person to person, so there always are going to be edge cases. But hey, it's just an arbitrary title, don't get so worked up over it.