If a poll is done with scrupulous methodology, it still has a margin of error. The pollsters themselves would not say this. If the population being polled at the time was all adults over 18 in the United States, one might reasonably conclude that a similar percentage of this population would have answered the poll's questions in the same way. Secondly, poll figures are always indicative of people's opinions in the past . By the time articles appeared in periodicals, the polls were over a week old.
Public opinion can change rapidly.
What was true a week ago may well not be true today. Issues that are perennial or long-standing such as opinions on abortion or capital punishment generally do not change quickly. However, issues that the public knows little about, such the situation in Haiti, or in Bosnia, often show significant changes in public opinion in short periods of time. This is also true of approval ratings. They can change rapidly.