A less quackish way to say the same thing is that a scientific paradigm tells people along which lines to look for answers. Looking at areas the paradigm doesn't recommend are generally not worthwhile, but occasionally you get something important, which doesn't fit in the current paradigm but will eventually help form the new paradigm.

A good heuristic could be "seems like a solid scientist in general, but this niche where he was a top level researcher led him to a split with the main stream" vs "consistently takes anti-mainstream views and has no contributions within the paradigm "