The Gallup question asked respondents how they would feel about “Democrats in Senate using a parliamentary procedure to avoid a Republican filibuster and pass healthcare bill by simple majority vote.”
At best, that means exactly nothing to most people. Worse, it sounds devious. “Using a parliamentary procedure to avoid” makes it seem like some sort of unprecedented trick (it isn't.) No wonder people oppose it.
Another problem: The question suggests the entire health care reform package would be passed using this trickery. In fact, reconciliation is generally being considered as a means of passing tweaks to the legislation that has already passed the Senate with 60 votes.
The results would, I suspect, be far different if Gallup asked a much more straightforward question: “Do you think passage of health care legislation should be decided by majority vote?” Or even the more-accurate-but-slightly-more-complicated: “Do you think passage of changes to the recently-passed health care legislation should be decided by majority vote?”
UPDATE: As I noted on The Twitter, if you ask people if they like "“heated ground
bovine flesh,” the results will be significantly less reliable than if you ask them about "hamburger." Keep it simple!