That'd be them, yes. They're pretty much the only remaining traces of the brotherhood in the region. For a reason.
The brotherhood came out to the Mojave with the intent of grabbing some tech and improving things in the region under the support of one of those wide eyed idealists (by typical/historical brotherhood standards, anyway). Pretty much a direct copy paste of what Lyons was doing in the capital wastes. While this has had some amount of success in some areas, this one happens to be a tough sell. Things obviously go far south and war breaks out with some of the other factions trying to get their hands on some priority tech. People die, shit hits the fans, and their leader kind of got a little nutty somewhere in the process.
As the only survivors of this whole thing, the HV BoS is obviously more than a little pissed off with the locals. Which leads to them behaving more like their distant forefathers than the more recent brotherhood policies (which happen to be a little bit more tolerant overall and some groups have even become outright helpful.).