This added context really drives the OP point's home. After all, it's relatively easy to be objective when the facts are overwhelming and communicated by a sen

This added context really drives the OP point's home. After all, it's relatively easy to be objective when the facts are overwhelming and communicated by a sensible and rational messenger. Under these circumstances, only the most pig headed caricature would cling to preconceived, faulty, notions. However, it's much harder to take seriously criticism that originates from a volatile and unpopular source. Doubly so if their own theory or notion is flawed. Under this circumstance, it's extremely easy to avoid self-observation. For instance, in this case it should not have mattered too much that Semmelweis's theory was demonstrably incorrect. What should have mattered was the clear causality linking disinfectant hand washing and a reduced rate of labor mortality. They had an easy out, and they took it. That reaction is all too common.