Uh, what? There isn't really such a thing as an "HD tuner." There are digital (ATSC) tuners, which receive digital broadcasts, which may or may not be HD. Virtually every HDTV ever made has one of these -- the ones that don't have to be called "HD Ready" or "HD monitors" rather than HDTVs. Most of them also have analog (NTSC) tuners, but that doesn't keep them from receiving HD signals.
Well, I would hope that work done by the Nielson Group is a little more scientific than the Everybody Votes Channel. For instance, one factor that could confound that poll is the possibility that people who are still amused by entertainment polls are a less tech-savvy group as a whole (and I say that without any snideness).