Believe me when I say I'm not on corporations' side and I think they get away with all kinds of immoral shit through craftiness in the legal system, but I think that the only intellectually honest answer is that suspicious linkages are not causality, and that it should be evaluated by someone wielding scientific impartiality and robust statistical and epidemiological methods, rather than a legal process. Unfortunately courts are a shit place to evaluate science or broadly reality.

PFOA and similar precursor chemicals are one of those areas where I think it should be easy to establish elevated risk of disease with epidemiology (they probably have, but it's not my field and I haven't looked), but there are a lot of other areas that are much less clear cut. I've seen firsthand the family's emotional response to cancer being to find a villain somewhere, and it was in a case where I think no villain ever existed. People behave irrationally with mortal disease, and unfortunately some of it is just bad luck.