I thought that if people had a trait that was usually privileged, they were just supposed to endure any mistreatment they received for it.
That's not actually a standard norm -- one thing worth noting is that when you look at the recent history of online SJ, what you're seeing is the proliferation of terms, tactics, ideas and theoretical frameworks from the last century, in a variety of contexts, suddenly become very visible and popular. Lots of people are discovering it, and in many cases what took decades or longer to develop in some groups is being adopted wholesale by people who are often familiar with summaries, or a few key texts.
A lot of people are finding it very empowering. Those people are not especially more likely to have deep insight, uncommon empathy, or a very broad view of the world than anyone else. This means they're going to be doing all the things people do in addition to talk about SJ, when talking about SJ.
Yes, this does mean some will be bullies, and sometimes whole groups will endorse that, essentially because in the process of bullying the person is also saying stuff they agree with, that they find empowering, and that is widely deprecated in society in general (often in ways that cause them tangible harm).
The trick is that bully-detection can run afoul of a related, but not similarly-pathological phenomenon. I wanna unpack this a little more because it's kind of complicated, and how well you see or agree that there's a distinction is often dependent on your own social values. It goes like this:
Some people have set up spaces to discuss some element of their experience in a SJ context -- say, a blog that deals with racism in popular culture, posted online. While technically anyone can access it if they know the URL, the blog is not written so as to be maximally-understandable to the widest cross-section of possible audiences. This is fine -- this is no different than discussing biology or astronomy publicly despite the sheer number of people who'd feel it was controversial to assert certain facts about evolution or cosmology, or who just don't know much about the topic.
People who aren't very knowledgeable about the topic, or have issues with it being discussed as a factual matter at all, may discover the blog and the discussion going on there. When they do, they'll often attempt to participate in the discussion from their own starting point, and when the immediate responses don't satisfy them, they'll keep pushing at it.
Thing is, it is really, emphatically not up to the bloggers or the commentators to bring them up to speed. It just isn't -- yes, education is important, yes communicating your point persuasively to outsiders is an important skill, but we don't expect the journal Nature to give everybody a basic, elementary-level understanding of physics before talking about the latest interesting results out of $LABORATORY. There's nothing especially wrong with pointing that out; doing so confrontationally might not seem very polite, but politeness may not actually be warranted either, as it'll merely encourage the person to keep demanding time and attention the folks there want for doing what it was they got together to do in the first place.
Explaining that this is not the place to come to be educated, or that it's not something they're volunteering to do, is seldom easy or productive to do gently. The goal is to get the person to stop trying to participate in a discussion they're derailing. Social and communication norms will play a big part in how that's phrased, too. It may be anything from arm's-length polite to trollish depending on the community and the individual involved. The common factor is that the purpose of communication on this topic is to end the discussion, which is consuming scarce resources of time, attention and energy.
I agree with Alicorn and NancyLebovitz that "social justice" discourse on the internet often suffers from echo-chambers and affective death spirals which give it an overall impression of being extremely phyg-ish and vulnerable to all sorts of biases and limited cognition.
The silver lining is that these detrimental features also eliminate its potential of exerting any kind of adverse influence on real-world politics and society. This is why I encourage people to refrain from commenting as "outsiders" on such blogs, so as to save their limited time and effort.
One of the lessons highlighted in the thread "Less Wrong NYC: Case Study of a Successful Rationalist Chapter" is Gender ratio matters.
There have recently been a number of articles addressing one social skills issue that might be affecting this, from the perspective of a geeky/sciencefiction community with similar attributes to LessWrong, and I want to link to these, not just so the people potentially causing problems get to read them, but also so everyone else knows the resource is there and has a name for the problem, which may facilitate wider discussion and make it easier for others to know when to point towards the resources those who would benefit by them.
However before I do, in the light of RedRobot's comment in the "Of Gender and Rationality" thread, I'd like to echo a sentiment from one of the articles, that people exhibiting this behaviour may be of any gender and may victimise upon any gender. And so, while it may be correlated with a particular gender, it is the behaviour that should be focused upon, and turning this thread into bashing of one gender (or defensiveness against perceived bashing) would be unhelpful.
Ok, disclaimers out of the way, here are the links:
Some of those raise deeper issues about rape culture and audience as enabler, but the TLDR summary is:
EDITED TO ADD:
Despite the way some of the links are framed as being addressed to creepers, this post is aimed at least as much at the community as a whole, intended to trigger a discussion on how the community should best go about handling such a problem once identified, with the TLDR being "set of restraints to place on someone who is burning the commons", rather that a complete description that guarantees that anyone who doesn't meet it isn't creepy. (Thank you to jsteinhardt for clearly verbalising the misinterpretation - for discussion see his reply to this post)