Kathy Sierra explicitly called out one of her harassers weev and his posse (def not what you'd call a "Social Justice Warrior", and weev initially copped to harassing her and has been trying to deny it subsequently).
Places like 4Chan and KotakuInAction are not some fucked up false flag operation simply by virtue of the vast number of man hours involved.
And even ignoring all of the evidence that contradicts your theory, i'd like to point out how incredibly unsympathetic and unhelpful your theory is.
Even if there were some psychotic cadre of rabble rousers out there harassing others, IT WOULD STILL NOT BE OKAY IN ANY WAY SHAPE OR FORM. And there would still be the very practical problem that people were being harassed.
There are people out there who are trying to address harassment on the internet with technological and social means, and despite the size of the challenge, this is something that needs to be addressed.