I had to go back and read to try and get a handle on where this conversation is even headed, and maybe it's silly to interject here, but the Xenophobe FE's don't consider the other races around the galaxy as non-sentient beings. Even if you see cows as food, no one argues whether or not they are alive: we simply consider ourselves superior to them. So superior in fact, if it turns out cows are arming up and building nuclear weapons we'd be a bit screwed because we'd never see it coming. At least not as things stand.
Even hardcore racists see their hated groups as sentient, what they do not acknowledge is they are people. You know, like "we" are. And in most cases, the most hardcore racist isn't oblivious to the danger their target groups present: in fact it's much of their rhetoric. Sure, depending on the gap there is a bit of complacency, "look at the natives with their spears and primitive ways" evolves as they acquire sub-machine guns. But, quite frankly, a xenophobic isolationist doesn't think the rest of the galaxy is filled with missile wielding cows, they see the galaxy as full of savages and primates whose backward ways and violent natures is a threat to "our civilized and proper way of life". The isolationist bit is just a description of how they deal with it: specifically stay the hell out of our neighborhoods.
