I once had a similar view on social justice movements. It is easy to claim the reasonable "moderate" position where you're essentially saying "I am generally in favor of your ideas, if you were a little bit nicer about them".
When I actually started to read what social justice activists were writing - I mean really read it, not just reading quote mines during unrelated discussions or exaggerated representations featuring the popular stereotypes - I found this position indefensible. A lot of what I read made me uncomfortable, so my immediate reaction was to bring out the usual responses for why they must be wrong or unreasonable if what they said made me uncomfortable. Only over time did I realize that I was uncomfortable because I knew they were right.
If some of those people had been "reasonable" and non-confrontational about formulating their beliefs, I probably would have never even challenged what I previously thought. Sometimes you just have to push against well-established ideas in peoples' minds where just a reasoned debate would be easily disregarded and have no effect.
In other words, if a social justice activist "fights", maybe it is because they have to fight to even begin to overcome to status quo they oppose.
By the way, that doesn't mean I disagree with your subsequent observation about some aspects of the culture around the social justice movement. I'm just skeptical why that is at all relevant and has to be constantly brought up and reinforced by using the SJW moniker.
For every political movement you will have the phenomenon that there is a minority of educated activists with the necessary rhetorical skills to communicate their position in a compelling manner. Most people who share their position may follow for good reason, but lack the skill to express it. Or they are just along for the ride because that political movement is their social environment.
This applies in the same way to people from well established political movements: have you ever seen people talk politics on Facebook? Never seen staunch and outspoken Democrats/Republicans who clearly had no clue about their own professed political position? This effect is further amplified for the social justice movement because it basically exists only on the internet, with no buttressing from credible looking politicians and traditional media that would drown out the crazies a bit.
(Not to mention that a disproportionate part of people in the SJ movement are teenagers who I think deserve to be cut some slack.)
This of course doesn't excuse all the problematic stuff going on in the SJ movement, but really is grounds for questioning the whole narrative that it is made up of only crazy people who can be easily dismissed. Because that is arbitrary. Instead, seek out the people who can actually express a reasoned position, and evaluate the movement on those terms. This is general advice for evaluating political positions by the way.