So that's who said it. Yep, that very quote came to mind after I paraphrased half of it unintentionally. So I used the rest. :)
Burke is credited for it but honestly the notion has been phrased and paraphrased over the ages, since long before Burke.
I don't know what I liked better: that there was a mastermind behind the conflict between the Avengers in the movie, or that there wasn't one bad guy subtly instigating the avengers but their ideologies just naturally clashed when it came to the superhero registration act, as in the comics.