People who argue that a hypothesis is inappropriate for a qualitative study do so because they believe that a hypothesis leads a researcher to approach the subject in a biased way. The researcher, it is believed, will tend to want to confirm the hypothesis.
In a quantitative study, this is not a problem. This is because the researcher will get numerical data that will prove or disprove the hypothesis. In a qualitative study, by contrast, the "data" must be interpreted. Since the researcher has to give meaning to the data, it is important not to have a preconceived notion of how the data will come out.
Therefore, in a qualitative study, one should ask things like "how will levels of education affect quality of life" rather than stating a hypothesis such as "people with lower educational levels will generally experience a lower quality of life than those with more education." Stating it as a hypothesis will generally lead the researcher to look for ways to support the idea that the quality of life is lower for less-educated people.