The use of correlation to support causation has been used since the dawn of man to spread propaganda and unscientific data. Even in recent times you can see this taking place all over the globe. The most recent case that I believe is the most hurtful to society is the claim that autism can somehow be attributed to vaccinations.
The fear spread back in 1998 when a fraudulent scientific paper published by the British Medical Journal was used to link vaccines, specifically the MMR vaccine, to autism. Over time this study was used by people to spread a biased agenda that had no real scientific backing. The so called evidence was spread using fear mongering and appeals to emotion, which caused many people to have biased views on the issue due to not unbiased and empirical.
The fact that the study was not able to be repeated shows that there is no hard evidence to support the original claim. In fact, the CDC, NHS, Institute of Medicine, and other bodies have found NO causal evidence linking the two together. Despite this, the propaganda is still being spread even though the original claim was disproven many times over.
How can we as a society continue to function if we let unscientific data run our society? Since 2009 the childhood vaccination rate for MMR has been around 90%, meaning that one out of ten children are not protected against measles, mumps, or rubella. If this kind of trend continues, a lot of unnecessary damage may impact us and our future generations. Instead of being lead down this road, we need to stop relying on just corollary data and focus on empirical data that follow the six principals of critical thinking.