To me a SJW is just an Edgelord by any other name.
Internet cancer is the homogeneity of opinion, attitude, and action.
When you encounter the same thing over and over again:
The internet itself starts to feel more like a impenetrable glowing brick wall of autism than a interactive virtual space.
My Facebook is a dead zone - a self-filling stamp collection of little demagogues - left - right - don't let them touch.
A lesser example for me: Let's Plays are a type of cancer on YouTube.
1. Because their output exceeds original content creators.
2. Your riding on somebody's coat-tails with pretensions of self-importance.
3. LPs are an ad (barring some exceptions of course).
What is deemed cancer can totally be subjective - not all LPs are done by screaming man-children - but think of the poor servers and the number of videos they upload to it.
Advise dog type memes, or for that matter reaction images are short-hand. I had a professor who had a melodramatic way of saying you "castrate yourself when you learn a language" - because you loose the potential to convey yourself differently. Some tiny crazy truth in that, but when it comes to net cancer we're talking bulk - a desert of what has already been said. Does a rage comic convey anything but sameness?
Originality is the only cure to net cancer - and I'm not talking about claiming special snowflake status, or crawling in my skin as an answer.
Originality isn't about peddling your ego, fetish, faith, or politics.