Well they do go all yellow and red box-y on you when they start targeting and shooting you like anyone else.
Yeah, it’s hard to say how much havoc these guys are causing yet. I think many of their ‘victims’ aren’t the sort to have the API linked to zKillboard, like the OP who doesn’t seem to have his linked so someone must have posted the kill mail manually. Further, I think the NPCs share names with the ones in the Resources Wars sites which are indeed killing a lot of players, but generally ones actively playing the game rather than loitering on a gate/station or in a belt. Still, perhaps some of these kills are from these new roaming NPCs:
Kudos to CCP for having the courage to implement these guys to highsec and setting themselves up for the obvious response from a subset of their highsec players. It feels like it has been a very long time since I have seen something truly new and mysterious happening in New Eden.
Edit: Actually maybe the NPC that killed the OP is unique to the roaming NPCs: