The person I attempted to contact was the graduate chair. I don't want to be too alarmist, however--it's possible they're on Spring Break, or flooded with eMails at this time, so I'll try to get into contact with more people. I agree with you, however, that it's a bit of a red flag, especially with what I've heard so far. I'll definitely keep trying at this point.
EDIT: I should also mention that I contacted a Ph.D student with similar interests who went through the MA program, but we've been unable to set up a time as of yet.
Yes, I am definitely looking to continue on to a Ph.D. The people I contacted at UNM had placement rates for the MA program that were really excellent, getting into programs like DePaul, Stony Brook, and Emory fairly consistently. Like I mentioned, I haven't been able to get into contact with the people at BC just yet.
Honestly, at this point I'm leaning towards UNM because the people I'd like to work with more closely align with my interests and what I've gleaned so far about the graduate school climate (as well as their placement being pretty stellar), but I know that at this point I've only really spoken to people from there. I also know that BC is on the east coast and so has greater proximity to conferences and networking opportunities.