The rejection of knowledge based on scientific studies has some serious consequences because it means that people are willing to reject factual information that provides evidence for suppositions about how the world works. Regardless of how much evidence exists for some suppositions, some people are willing to reject everything related to them. Some will go out of their way to try to convince legislators and the general public that scientists are not doing objective, reliable work but are instead crying wolf about imagined problems.
When you reject evidence out of hand, you are rejecting knowledge. Knowledge is what we know about the world around us, so rejecting facts and evidence is equivalent to rejecting reality.