«Woodward advocates no ideas and is indifferent to the fate of government. His fabled access has been in the service of his technique of accumulating mountains of facts whose scale fosters an image of omniscience. As his bestsellers and wealth piled up, he lost a sense of journalism as provisional and inherently imperfect, seeing it instead as something engraved in stone. But his method made him particularly vulnerable to manipulation by cunning sources.»
--"No more Watergates": Bob Woodward brought down Nixon, but failed to exhibit the same scepticism about Bush
The easiest way to end up thinking something is "engraved in stone" is professionalism.
Professionalism is doublethink, and groupthink, and dumb. It replaces "what is right?" with "what rule do you think I broke?".