Steve Benen points out that when Republicans were crusading against the Affordable Care Act, a major talking point was "The American people have made it clear they don't want this." There was much talk of it being crammed down their throats and public reaction was reason enough to not pass the plan. Of course, nowadays those same American people are saying overwhemingly that they don't want Medicare changed and they do want to see taxes raised on the wealthy…and that matters not to Republicans.
And I guess you can turn the hypocrisy around there: Democrats shrugged aside the fact that polls said the people didn't want the A.C.A. and said "They don't understand it" and/or "They'll learn to love it," and now the opinion polls will be a strong argument for the Democratic plan for the budget. This is all a corollary to the principle that a poll that tells you what you want to hear is an honest, scientific sampling and later, when the same pollsters tell you something that hurts your cause, they're biased and their poll isn't valid because they took it on a Tuesday and everyone knows Tuesday polls are inaccurate.