Part of it is all the fear mongering out there from the small blocks camp, as well as just the human psychology/sociology involved. A lot of people simply won't make a decision until they see others have already decided, and the existence of Not Bitcoin XT doesn't help that one bit. It proves that we don't even *have* an accurate way for people to find out how many other people have already gotten on board.
More to the point it proves that the people opposed to XT don't want anyone to know how many other people are on board because they are fully aware that if people had accurate information about it, they'd be the losers.
If the anti-XT people are that sure they're losing, why should any of the rest of us doubt?