SWJ wasn’t a popular acronym 10 years (let alone 15) ago in the online communities I hung around in. ;)
replySure, I get that. But the term gained popularity in 2012 it seems, according to google trends.
replyhttps://trends.google.com/trends/explore?date=all&q=SJW&hl=e...
And there's a entry from 2011 in urbandictionary.com, so maybe that's around when it was coined.