Eh, they'll just delete them all and retreat further into their hugbox, feeling justified that there's alt-right Nazis out to murder them. Give them an external threat and they'll stop eating their own.
The best trolling these places get is from people who Poe's Law the forums, because they can never be quite sure whether someone's just taking the presumed shared beliefs of the forums just to their next logical step, or if it's someone fucking with them. Riles up the paranoia and struggle sessions something fierce. Of course, that does take more effort than spamming memes, but less than you think. You could even treat it like those chess games where it looks like you're playing two people, but you're actually just copying your opponents moves to have them play each other; grab a few posts from ResetEra and post them verbatim on RPGNet and vice versa and you've got your crazy SJW material all ready to go.