I can guarantee that it's not. I first heard the term 'social justice warrior' as a label from people who were fighting human trafficking (freeing modern day sl

I can guarantee that it's not. I first heard the term 'social justice warrior' as a label from people who were fighting human trafficking (freeing modern day slaves) and they were proud to label themselves 'social justice warriors'. This was around 2012, long before the 'alt right' was a group or label. Over time the people who claim to be 'social justice warriors' and the people who get labelled SJW by others has changed, but the term didn't originate from the Alt Right, and it definitely didn't originate from something people called someone else. The first users who popularized the term applied it to themselves.