I don't consider all BLM protestors to be SJWs (I'm using SJW in the pejorative/stereotype form). I'm sure some/many are, but not all.
But BLM is primarily *anti-police-brutality*, so all protestors / participants are *necessarily* *progressive* in their politics, since they're challenging police civil (extra-legal) hegemony.
Why would you want to *stereotype* people as a component of your politics -- ? (Who *deserves* stereotyping and being-condescended-to, based on a stereotype, and for what reasons?)
Isn't being against police brutality a *valid*, real-world politics -- ?
My point here is that the psychological mechanisms that govern how zealots behave, left or right, is the same.
You're mischaracterizing *politics* with this label of 'zealot' -- the term describes those of the make-believe / imagined realm of *religion*. Politics tends to be about real-world events, pertaining to power relations and economics.
Since you're indicating political events of *large-scale* importance, the *psychological* approach is an *inappropriate* one -- it's not just one or a few people who are "SJW"s, or BLM protestors, it's an *international* movement, currently, that's addressing the real-world social ill of police brutality and killer cops, particularly in the U.S.
Your use of the term 'SJW' is politically *slanderous*, *because* you're being vacuously perjorative and stereotyping, and self-admittedly, too.
Social justice warrior (SJW) is a pejorative term for an individual who promotes socially progressive views, including feminism, civil rights, and multiculturalism. The accusation that somebody is an SJW carries implications that they are pursuing personal validation rather than any deep-seated conviction, and engaging in disingenuous arguments.
The phrase originated in the late 20th century as a neutral or positive term for people engaged in social justice activism. In 2011, when the term first appeared on Twitter, it changed from a primarily positive term to an overwhelmingly negative one. During the Gamergate controversy, the negative connotation gained increased usage over-shadowing its earlier origin.
According to Martin, the term switched from primarily positive to negative around 2011, when it was first used as an insult on Twitter. The negative connotation has primarily been aimed at those espousing views adhering to social progressivism, cultural inclusivity, or feminism. Scott Selisker, writes in New Literary History that the SJW is often criticised as the "stereotype of the feminist as unreasonable, sanctimonious, biased, and self-aggrandizing". Use of the term has also been described as attempting to degrade the motivations of the person accused of being an SJW, implying that their motives are "for personal validation rather than out of any deep-seated conviction". Allegra Ringo in Vice writes that "in other words, SJWs don't hold strong principles, but they pretend to. The problem is, that's not a real category of people. It's simply a way to dismiss anyone who brings up social justice."
The term's negative use became mainstream due to the 2014 Gamergate controversy where it emerged as the favored term of Gamergate proponents and was popularized on websites such as Reddit, 4chan, and Twitter. Gamergate supporters used the term to criticise what they saw as unwanted external influences in video game media from progressive sources. Martin states that "the perceived orthodoxy [of progressive politics] has prompted a backlash among people who feel their speech is being policed". In Internet and video game culture the phrase is broadly associated with a wider culture war that also included the 2015 Sad Puppies campaign that affected the Hugo Awards.
In August 2015, social justice warrior was one of several new words and phrases added to Oxford Dictionaries.