Duncan Watts and Harrison White

I've been reading Duncan Watts' Six Degrees and it's a very engaging book but this sentence stopped me stone cold:

Harrison is famous not only for his irascible manner and impenetrable writing but also for his profound generosity, astounding breadth of interest, and occasionally startling insight.

Occasionally startling insight? Only "occasionally"? Is this supposed to be a compliment? A backhanded compliment? An outright insult? Hmmmmm.