it would be unsurprising that a subset of moderators develop PTSD-like symptoms related to that experience.
Is that really the case? Most moderation is done on textual-based forums, like the one we're on right now. I'm having a hard time imagining the right combination of words on a screen to generate trauma in the requisite quantities for someone to wind up with a clinical disorder because of it.
Personally, I've been on both sides of this coin. I've been the guy kicking trolls off of a decent sized board, I've been the guy getting kicked off because I annoyed the wrong person.
At no point did it ever progress beyond internet drama. The meanest, nastiest person I could imagine could type in words along the lines of how they'd like to kill and fornicate with my mother, and my, and most other people's response I wager, would be "That's cool, kid. Bye now. Ban"
Maybe there's a case to be made for becoming jaded after a while of dealing with the worst (hang out on the meta Stack Exchange sites for a publicly visible example) - but PTSD symptoms? To me, that both overly glorifies the troll "i can type words so good that I can make other people have legitimate mental breakdowns!" and makes light of the suffering by people who actually have PTSD (who have seen things like people dying). It feels like a lack of perspective, brought on by spending a lot of time online. Unlike real life, disconnecting from online drama is always a button press away.