The Sokal Hoax goes back more than 2 decades. Any strong connection to the pejorative SJW epithet seems a bit of a stretch to me.

https://www.google.ca/#q=sokal+hoax

Did Sokal use the term SJW?

If memory serves Sokal's primary goal was to expose  Postmodernism ("Everything is Relative") and the weak content editing standards of what posed as reputable Academic Journals promoting Postmodernism. 

Science deals with objective reality. Someone I knew in a 1971 Secondary School class thought yogic mattress hopping could lead to telekinesis. I hope he never tried that off a tall cliff or building.

Doug Henning wanted us to fund a Canadian Corps of Yogi mattress hoppers, paid as Senior Civil Servants, when he was featured as a "Natural Law" party Federal Candidate in Canada. Could you ever make up stuff like that, even if you tried?