A drone operator may have to remain on station with cameras zoomed in on the target they have just hit, and therefore have to witness the immediate aftermath of what they have done. By comparison a fast jet crew would not be able to see everything in the same manner simply because they do not have the equipment to enable them to do so.
That's what OC 13 is saying, I think, and I can see where he is coming from.
I am not deriding that they may suffer from it, but then you could watch similar on Live Leaks, so does that mean viewers of that channel could also suffer from PTSD from viewing the strike and aftermath?