I encourage you all to checkout True Believer. Specifically the part about converts:
https://en.m.wikipedia.org/wiki/The_True_Believer#Part_2._The_Potential_Converts
The key points laid over this question of SJWs:
1. Alienation. Not having traditional social fabric/support, sense of belonging, and meaningful rites of passage leading to firm role in community. Obviously this applies to many people in Western societies and particularly to people drawn to Chan culture.
2. Unmet economic expectations. He calls them "the new poor" but it can simply mean someone raised in say, a solidly middle class family during good economic times who comes of age in deteriorating markets with reduced opportunity. Certainly this applies to millenials even before we consider the load of unrealistic expectations we were fed by the "self esteem" movement and Western aspirational culture/marketing in general.
3. Misfits. This is vague in the wiki, but he's lassoing all the people who would likely be discontent and disenfranched such as the physically and mentally ill. Along with that we include the frustrated underachievers, genuinely wronged by some establishment, and those who are simply miserable but unwilling to improve by healthy means. Ring any bells?
The book makes a point to explain that these generally unhappy people can easily join any mass movement which offers them a sense of belonging, empowerment, and purpose. Further they can easily switch ideologies because the words are secondary to the function of emotionally compensating for their discontentment.
Mass movements demand a stripping away of individuality. For these flexible converts, they already feel self loathing. Their unsatisfying and unexamined lives are willing plastic.
Finally, in case of progressive politics, the movement has solidified as an establishment which offers economic and social advancement beyond what many misfits could achieve -- unless they become true believers.