Association Not Causation
Correlation measure association. But association is not the same as causation
there could be a strong correlation between fat in diet and cancer. However it may not be the causation of cancer or if it is it could be hard to single out.
For example countries who consume large amounts of fat also consume large amounts of sugar and carbohydrates. Therefore we shouldn't single out meat as being the only factor of causation. Even though there is a strong correlation. It could be Fat consumption, Sugar, or Carbohydrates or all of them combine that is causing the cancer.