Discourse started getting more difficult, let's see... was it after the Hitler-Stalin Pact when the Communist Party USA identified the sin of "premature anti-fascism"? Or was it in the late 40s and 50s when Joseph McCarthy, Republican Senator from Wisconsin, began a witch hunt for "are you now or have you ever been" communists and homosexuals in the U.S. Government? Or was it during the war on Vietnamese communists that "we had to destroy a village in order to save it"? Or was it when "socialist" became a term of opprobrium equivalent to 'pedophile'. 'subversive' and 'communist'? In the 1980s some socialists were wondering whether they should just stop using the term. Alas... there wasn't any other term as serviceable as "socialist".
And so on and so forth down to the present. The "Overton Window" - the range of ideas tolerated in public discourse - changes over time, certainly.
Race and/or ethnicity, sex and/or gender, any number of identities, and feminism don't seem to have been shut out of the Overton Window. (Like, "Would the love that dare not speak its name please shut up for a while!") Some operatives in the swamp of the right wing may ridicule social justice warrior operatives in the left wing swamp on the other side of the road. If "SJW" is the worst epithet right wingers can come up with... stop worrying.
I don't find SJW as dismissive a handle as you two seem to find it. It seems like a good fit, to me. SJW is no more offensive than "weekend warrior". I've been a "social justice warrior" a number of times. Also a "do gooder". SJW is less derisive than "do gooder". It's better than "guilty white liberal"; it beats "dead white males" -- a category to which I'm close enough to be touchy about.
The efforts of the majority of people committed to the fight for social justice strike me as very similar to the the efforts of anti-war peace activists during Vietnam--efforts that I thought very highly of at the time. We marched to Boston Commons (or wherever the location was) and chanted slogans and sang "we shall over come" and listened to impassioned speeches. Then we went home.
There was an enormous amount of talk among small groups, tons of planning, lots of leaflets and buttons were printed, arguments had with family and friends, and so on. A million people showed up one fall day in Washington, D.C. -- 1 out of every 200 Americans overflowed the mall for that biggest peace demonstration.
And you know what the concrete outcome of all this was? PFFT. Zilch. Zero. Nada. The war lasted another 5 years, unabated. It is as safe to criticize SJWs now as it was to criticize hippie faggot peaceniks in 1970, because there was very little of importance that hinged on their efforts.
I disparage social justice advocates now no more than I disparage peace efforts 50 years ago. But let's be clear: Neither peace advocates nor social justice advocates ever got anywhere close to getting their hands on the levers of social and economic policy. Those levers are never left unattended or unguarded and they are well protected behind locked thick-steel doors.
The benefits of social justice advocacy and peace activism flow primarily to the activists, to the benefactors--not to the beneficiaries. Why? Because the act of protesting is good for the protestor. Literally. It's a healthy exercise in every sense of the word. It just happens to be totally ineffective as a method of getting at those policy levers.