Categorical statements

I don't think your analogy works the way you intended. My comment is equivalent to cautioning those who told Stevenson about seizures, or Max Planck for his accusations of "heresy", or Einstein about his vehemence. One should be more humble.

"The corollary to this is that if no-one lays down the "facts" to be challenged, the human instinct for contrariness doesn't get aroused as much"

Now this "corollary" needs somewhat more evidence to convince that naysayers are a necessary (or necessarily positive) factor in innovation.