The best answer to the question "Why can the scientific method not be used to make value judgements?" is:
Science can only provide data, but it cannot tell people what to do with that data.
The scientific method focuses on observation, experimentation, and evidence, allowing scientists to draw conclusions based on empirical data. However, value judgments—involving ethics, morals, and personal beliefs—require a framework that goes beyond data and facts. Therefore, while science can inform decisions, it doesn't dictate the ethical implications of those decisions.