On both sides of this debate, I think there could be a bit of "retrofitting" the events of 50 years ago through a contemporary lens(sorry if that's a mixed metaphor).
To say "Rockefeller wouldn't care about one music festival, it wasn't a riot. Freedom of assembly etc" might betray an outlook that's grown up in a world where The Who plays the Super Bowl, flag-burning has been okay for over twenty years, middle-class office workers access porn on their lunch breaks with a click of their cell phones, and marijuana legalization in one form or another is the law in a majority of states. That WASN'T the world of 1969, especially not among Rockefeller and his fan base, and he may very well have made not much distinction between a gathering of hippies, known to do drugs and romp amorously in public, and a gathering of leftists of the type who had been engaged in highly agressive, if not outright violent, protests across the country. (And yes, I realize the right-wing was doing bad stuff too, probably worse.)
On the other hand, assuming that Rocky's immediate response to the festival would have been to say "Send in the guards!!" might reflect a worldview that grew up knowing how singular and iconic Woodstock is considered by later generations. IOW assuming that Rockefeller would have attached the same significance to it that we do today.
One thing I'll note is that there seem to be at least two different versions of the story: one in which Rockefeller wanted to use the Guard to control the crowds and traffic, and one in which he wanted to use it to shut down the festival entirely.