Quoting people out of context is also rude. Examples A and B, I know, were both in repsonse to "it's justified when we do it because x group does it", a rhetorical ploy I have never found convincing for the exact reason I was pointing out. We are neither terrorists nor chimpanzees, so their conduct cannot be used as a standard for evaluating our own behavior. If Emily or anyone else is upset that I have taken their "we" statements and turned them into "I/you" statements, that's a sign of illogic in and of itself. You are human and so am I. If you say that you believe "humans are inherently violent, like chimpanzees" then you are either saying "I am inherently violent, like a chimpanzee" or "I am not a human". You are also saying to the person you're talking to "I think you are inherently violent, like chimpanzees". Or, more likely, you simply haven't thought about the implications of your argument at all.
I note that in the terrorist example, though of course you offered no context, if I am remembering correctly Emily was calling for an escalation of brutal tactics in Afghanistan, an already vicious war that took the lives of hundreds of thousands of innocent people and initiated scourges of illness, malnutrition, and homelessness in both Afghanistan and in refugee communitees in the US, that continue to this very day. That, calling for an escalation of that massacre, is to me a much more egregious form of "incivility" than observing that a fellow forum poster has, in fact, said something cruel after they said something cruel. If you call for someone's death, you have no grounds to complain if in response they call for your well-deserved public shaming for it.